> ## Documentation Index > Fetch the complete documentation index at: https://www.zippendo.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Connect GLS Germany, Austria, Belgium, France or Ireland > Connect GLS Germany, GLS Austria, GLS Belgium, GLS France or GLS Ireland under Carriers with the Client ID and Client secret of your GLS app and your GLS Contact ID, plus the optional Shop Returns app ID and Test mode. Covers products, customs outside the EU, express outside Europe, Pick&Ship and Pick&Return, Shop Returns, pickups and tracking. **GLS Germany**, **GLS Austria**, **GLS Belgium**, **GLS France** and **GLS Ireland** send GLS parcels through **ShipIT**, GLS's shipping system in those countries: parcels within the country, across the EU and to Switzerland, Norway, the United Kingdom and the rest of Europe outside the EU, next-day express, express outside Europe, delivery to GLS ParcelShops and parcel lockers, collections with Pick\&Ship and Pick\&Return, and return labels and QR codes for your customers' returns. Each country is its own card on **All carriers**, and all five use the same form. **GLS Belgium** also ships from Luxembourg. GLS in Denmark is a different card with its own form: see [Connect GLS Denmark](https://www.zippendo.com/docs/how-to/connect-gls.md). For Croatia, the Czech Republic, Hungary, Slovakia, Romania, Slovenia and Serbia, see [Connect GLS (MyGLS)](https://www.zippendo.com/docs/how-to/connect-gls-mygls.md); for the Netherlands, [Connect GLS Netherlands](https://www.zippendo.com/docs/how-to/connect-gls-netherlands.md). The fields that every carrier shares are on [Carrier credentials](https://www.zippendo.com/docs/how-to/carrier-credentials.md). > [!NOTE] > > You do not pick a sender address on this form. Add your addresses under the organization menu → **Manage** → **Addresses**. You choose the sender address on each shipment or in a [shipping rule](https://www.zippendo.com/docs/how-to/shipping-rule-fields.md). Connect the card for the country your GLS contract is with. Every outbound product ships from an address in that country (for **GLS Belgium**, Belgium or Luxembourg). Returns can come from further away: see **After you connect**. ## Before you start * A contract with GLS in the country you connect, and your GLS **Contact ID**: the ID GLS gave you with the contract that your parcels are shipped from. * Your own app on GLS's developer portal, with its **Client ID** and **Client secret**. GLS must enable the app for ShipIT and for your Contact ID: ask your GLS contact to arrange it. Zippendo books with your app, so your parcels and invoices stay on your own GLS contract. * To send outside the EU, GLS must also enable your app for its **Customs API**: Zippendo sends the customs data of each parcel there. * For **GLS Shop Returns label** and **GLS Shop Returns QR code**, GLS must also enable your app for its **Shop Returns API** and give you a **Shop Returns app ID**. Not needed with **Test mode** on. * For **Test mode**, an app and a Contact ID that GLS has enabled for its test system. Your live app does not work there unless GLS enables it for testing too. You can connect the same GLS country more than once, for example once per Contact ID. Give each connection its own **Carrier name**. **Learn more** on each card opens that country's GLS website. ## Connect your GLS country **1. Open All carriers** In the sidebar, click **Carriers**, then open the **All carriers** tab. **2. Find your GLS country** Find the card for the country your GLS contract is with: **GLS Germany**, **GLS Austria**, **GLS Belgium**, **GLS France** or **GLS Ireland**. Click **Connect** on it. **3. Fill in the form** The **Connect carrier** window opens. Enter a **Carrier name**, your **Client ID**, **Client secret** and **Contact ID**. **Shop Returns app ID** and **Test mode** are under **Optional fields**. **4. Connect the carrier** Click **Connect**. You see "Carrier connected", and the carrier appears on the **My carriers** tab. ## Fields on the form | Field | Required | What to enter | | - | - | - | | **Carrier name** | Yes | The name you see on **My carriers** and when you pick a carrier on a shipment. It starts as the card's name, for example **GLS Germany**. | | **Brand** | No | Shown only if your organization has [brands](https://www.zippendo.com/docs/how-to/create-a-brand.md). The form says: "Only this brand can use this carrier." Leave it empty to let every brand use it. | | **Client ID** | Yes | The Client ID of your app on GLS's developer portal. The form says: "The Client ID of your app on GLS's developer portal, which GLS Germany has enabled for ShipIT." The country is the card's own name. | | **Client secret** | Yes | The Client secret of the same app, exactly as GLS shows it. | | **Contact ID** | Yes | Your GLS Contact ID, without spaces, at most 20 characters. The form says: "Your GLS Contact ID, as issued by GLS Germany with your contract." | | **Shop Returns app ID** | No | Only for **GLS Shop Returns label** and **GLS Shop Returns QR code**: the app ID GLS sent you when it enabled Shop Returns. The form says: "Only for the GLS Shop Returns label and QR code products: the app ID GLS enabled for Shop Returns, as GLS sent it to you." | | **Test mode** | No | A checkbox, off by default. On: GLS's test system. Off: GLS's live service. The form says: "Use GLS's test system. Requires an app and a Contact ID that GLS enabled for testing." | **Connect** does nothing until **Carrier name**, **Client ID**, **Client secret** and **Contact ID** have a value. Zippendo saves your details without checking them with GLS. A mistake shows up the first time you send a shipment. ## After you connect The carrier appears on **My carriers** with a **Connected** badge and a **Beta** badge. You choose the product on each shipment or in a shipping rule, not on this form. See [Carrier products and services](https://www.zippendo.com/docs/how-to/carrier-products-and-services.md). | Product | Use it for | | - | - | | **GLS BusinessParcel** | Delivery to an address in the carrier's own country. **GLS Belgium** delivers in Belgium and Luxembourg. | | **GLS EuroBusinessParcel** | Delivery to an address in another EU country that GLS serves by road. Not Cyprus or Malta, and from **GLS Ireland** not Croatia. | | **GLS Parcel outside the EU** | Delivery to an address in Europe outside the EU, with the customs data GLS needs. See **Customs outside the EU**. Not offered by **GLS France**. | | **GLS ExpressParcel** | Express delivery the next working day to an address in the carrier's own country (for **GLS Belgium**, Belgium). Add a delivery window as a service, or leave it off for delivery by the end of the day. **GLS France** delivers by 13:00. | | **GLS ParcelShop Delivery** | Delivery to a GLS ParcelShop you choose on the shipment. Within the country, and to Austria, Belgium, Denmark, Finland, France, Germany, Ireland, Luxembourg, the Netherlands, Poland, Portugal and Spain. From **GLS Austria**: Austria, Belgium, Denmark, Germany and Poland. From **GLS Ireland**: those countries, not Ireland. | | **GLS Parcel Locker Delivery** | Delivery to a GLS parcel locker you choose on the shipment, within the carrier's own country (for **GLS Belgium**, Belgium). Not offered by **GLS Ireland**. | | **GLS ShopReturn** (return shipment) | A return label your customer takes to a GLS ParcelShop. GLS delivers the return to the address on your GLS account. **GLS Germany** and **GLS Austria** also take returns your customer hands in elsewhere in the EU. | | **GLS Express outside Europe** | Express delivery to an address outside Europe, with the customs data GLS needs. **GLS Germany** and **GLS Austria** only. See **Express outside Europe**. | | **GLS Pick\&Ship** | GLS collects the parcel at the sender address on the shipment and delivers it to the receiver. See **Pick\&Ship and Pick\&Return**. | | **GLS Pick\&Return** (return shipment) | GLS collects the return at your customer's address and delivers it to the address on your GLS account. See **Pick\&Ship and Pick\&Return**. | | **GLS Shop Returns label** (return shipment) | A return label your customer takes to a GLS ParcelShop in their own country. See **Shop Returns label and QR code**. | | **GLS Shop Returns QR code** (return shipment) | A QR code your customer shows at a GLS ParcelShop instead of printing a label. See **Shop Returns label and QR code**. | Only **GLS Parcel outside the EU** and **GLS Express outside Europe** go outside the EU. Every other product stays inside it, and none goes to the Canary Islands, Ceuta and Melilla, or Åland. Northern Ireland (postcodes starting with BT) is not offered. Each product shows its weight range on the shipment. A parcel takes at least 0.11 kg. Within the country the limit is 40 kg in Germany, 31.5 kg in Austria and Belgium (50 kg for **GLS ExpressParcel** in Austria) and 30 kg in France and Ireland. A parcel to another country takes 40 kg from Germany and Austria, 31.5 kg from Belgium and 30 kg from France and Ireland, and a parcel to a ParcelShop in another country, or a return from another country, at most 20 kg. **GLS Parcel outside the EU** takes 31.5 kg (31 kg from Ireland). **GLS Express outside Europe** takes 50 kg, and less to some countries: see **Express outside Europe**. **GLS Pick\&Ship** and **GLS Pick\&Return** take the same weight as a parcel within the country. **GLS Shop Returns label** and **GLS Shop Returns QR code** take the same weight as **GLS ShopReturn**. Zippendo stops a heavier parcel before the shipment reaches GLS. ### Labels GLS returns one label per parcel, except for **GLS Pick\&Ship** and **GLS Pick\&Return**, where the driver brings the label, and **GLS Shop Returns QR code**. Choose **Label format** on the product: **PDF**, or **ZPL (thermal)** for a 203 dpi Zebra label printer. The shipment's **Documents** tab lists the label size as **100x150**. A shipment with several parcels is one GLS shipment: every parcel gets its own label and parcel number, in parcel order. Give every parcel a weight. Zippendo does not send a parcel without one. GLS issues each label once, when you send. Zippendo keeps it on the shipment's **Documents** tab, so you can open and print it again from there. If GLS books the shipment but returns no label, the shipment shows a warning. Do not send it again: ask GLS for the label. ### ParcelShops and parcel lockers (service points) **GLS ParcelShop Delivery** and **GLS Parcel Locker Delivery** deliver to a service point. Choose it in the **Service point** section of the shipment before you send. The search lists up to 20 GLS points nearest the receiver's postal code, in the receiver's country: ParcelShops for **GLS ParcelShop Delivery**, and parcel lockers for **GLS Parcel Locker Delivery**. See [Pick a service point](https://www.zippendo.com/docs/how-to/pick-a-service-point.md). Both products need the receiver's email address or phone number, because GLS sends the pickup notice there. Zippendo does not send the shipment without one. ### ShopReturn Use **GLS ShopReturn** in a shipping rule for return shipments (**Inbound**). See [Inbound and returns](https://www.zippendo.com/docs/how-to/inbound-and-returns.md). Your customer is the sender: GLS prints their address on the label, and delivers the return to the address GLS holds for your Contact ID. Every parcel gets its own return label, plus a receipt your customer has stamped at the ParcelShop as proof they handed the parcel in. The receipt is stored on the shipment next to the labels. ### Pick\&Ship and Pick\&Return GLS collects the parcel at the pickup address, so nobody has to hand it in. The driver brings the label, so the shipment has no label and no warning about one. * **GLS Pick\&Ship** collects at the sender address on the shipment, in the carrier's own country, and delivers to the receiver. From **GLS Germany** the receiver can be anywhere GLS delivers by road in the EU; from the other countries, within the country. * **GLS Pick\&Return** collects at your customer's address and delivers to the address GLS holds for your **Contact ID**. Use it in a shipping rule for return shipments (**Inbound**). See [Inbound and returns](https://www.zippendo.com/docs/how-to/inbound-and-returns.md). **GLS Germany**, **GLS Austria**, **GLS France** and **GLS Ireland** also collect elsewhere in the EU by road (from Ireland, not in Croatia); **GLS Belgium** collects in Belgium and Luxembourg. The pickup address needs a phone number, because the driver calls ahead. GLS collects on its next working day. A shipment created through the [Zippendo API](https://www.zippendo.com/docs/api-reference/overview.md) can ask for a later pickup date: a Saturday or Sunday is refused. A pickup time window is not sent to GLS. You do not need to schedule a pickup under **Pickups** for these products: the booking is the collection. ### Shop Returns label and QR code **GLS Shop Returns label** and **GLS Shop Returns QR code** are return shipments (**Inbound**) through GLS's Shop Returns service. Your customer is the sender and hands the parcel in at a GLS ParcelShop in their own country. GLS delivers it to the receiver address on the shipment, in the carrier's own country. * **GLS Shop Returns label**: a 100x150 mm label. With PDF, the second page holds your customer's instructions and a receipt the ParcelShop stamps. Choose **Label format** as for other products. * **GLS Shop Returns QR code**: no label. The shipment's tracking information shows **Open QR code**: send the QR code to your customer, who shows it at the ParcelShop. Not offered when your customer is in France, Ireland, Bulgaria, Estonia, Finland, Latvia, Lithuania or Sweden. Your customer can return from any EU country GLS serves by road except Cyprus and Malta. Spain, France, Italy and Sweden need your customer's email address. One shipment is one parcel: for several parcels, create one return per parcel. Without **Test mode**, both products need the **Shop Returns app ID** on your connection. GLS sets up each country your customers return from for your app; a country it has not set up shows on the shipment as a settings problem. ### Express outside Europe **GLS Express outside Europe** goes from **GLS Germany** to Australia, Brazil, Canada, China, Hong Kong, Israel, Japan, Malaysia, Singapore, South Africa, Taiwan, the United Arab Emirates and the United States. From **GLS Austria** it goes to Australia, Bangladesh, Brazil, Canada, China, Hong Kong, Israel, Japan, Macao, Malaysia, Nepal, New Zealand, the Philippines, Singapore, South Africa, South Korea, Taiwan, Thailand, the United Arab Emirates, the United States and Vietnam. For other countries, ask your GLS depot. India and Indonesia are not offered. It needs the same customs data as **GLS Parcel outside the EU** (see **Customs outside the EU**), and also: * An email address and a phone number on both the sender and the receiver. * For a receiver in the United States or Canada, the receiver's state or province in **Receiver's state**, for example NY or ON. A developer using the [Zippendo API](https://www.zippendo.com/docs/api-reference/overview.md) can also send it as a receiver attribute named `state`. A parcel takes at most 50 kg. From **GLS Germany**, a parcel to China, Hong Kong, Japan, Malaysia, Singapore, the United Arab Emirates or the United States takes 40 kg. From **GLS Austria**, a parcel to Australia, Bangladesh, New Zealand or the Philippines takes 30 kg, and to China, Hong Kong, Japan, Macao, Malaysia, Nepal, Singapore, South Korea, Thailand, the United States or Vietnam 40 kg. Goods in EUR may be worth up to 5,000 EUR per parcel from Germany and 3,500 EUR per parcel from Austria. The **Incoterm** codes GLS takes differ per country, for example only 40 to Brazil from Germany. ### Customs outside the EU **GLS Parcel outside the EU** goes to Switzerland, Liechtenstein, Norway, the United Kingdom, Iceland, Albania, Montenegro, Bosnia and Herzegovina, Kosovo, North Macedonia, Serbia, Turkey, Andorra, Gibraltar, the Faroe Islands, Greenland, San Marino and Vatican City. From **GLS Ireland** it goes to the United Kingdom only. **GLS France** does not offer it. When you send, GLS creates the parcels and Zippendo then sends GLS the customs data, so it travels with the parcel. Fill in before you send: * On every order line: **Description**, **Tariff number** (the HS code, 8 or 10 digits), **Country of origin**, **Quantity**, **Unit price** and **Currency**. All lines use one currency. See [Customs and documents](https://www.zippendo.com/docs/how-to/customs-and-documents.md). * Your **EORI** number under your organization's or brand's customs identifiers. Zippendo adds it to every shipment. * The receiver's email address or phone number. * For a business receiver in the United Kingdom, the **Receiver's EORI number** on the receiver. It must start with the receiver's country, for example GB. Zippendo checks all of this before it sends the shipment, and names the order line that is missing something. Each product shows three options: * **Incoterm**: who pays duties, taxes and the clearance fee, as a GLS code. Without a choice, Zippendo sends 10 (DDP) when the shipment's **Delivery terms** are DDP and 20 (DAP) otherwise. GLS takes only some codes to some countries, for example 40 or 50 to Iceland, and 10 or 18 to a private receiver in the United Kingdom. Zippendo stops a code GLS does not take there and lists the ones it does. * **Export declaration MRN**: goods worth 1,000 EUR or more need an export declaration. Enter the MRN of the one you filed. * **GLS files the export declaration**: GLS files it for you instead, charged separately. If GLS refuses the customs data, Zippendo cancels the parcels at GLS and the shipment shows GLS's reason. Correct it and send again. If GLS does not confirm the customs data, or cannot cancel a parcel, the shipment keeps its labels with a warning: do not hand the parcel over before GLS confirms its customs data. ### Services Choose services on the shipment or in a shipping rule. Each product lists the services GLS offers for that country and route. For **GLS BusinessParcel** within the country: | Service | Germany | Austria | Belgium | France | Ireland | | - | - | - | - | - | - | | **FlexDeliveryService** (the receiver steers the delivery from GLS's email) | Yes | Yes | Yes | Yes | Yes | | **Guaranteed24Service** (guaranteed next working day) | Yes | No | No | No | No | | **SignatureService** | Yes | No | No | No | No | | **AddresseeOnlyService** (handed only to the named receiver) | No | No | Yes | No | No | | **DepositService (place of deposit)** | No | No | Yes | No | No | | **CashService (cash on delivery)** | Yes | Yes | No | No | Yes | | **AddOnLiabilityService (insurance)** | No | Yes | No | No | No | * **FlexDeliveryService** needs the receiver's email address. * **DepositService (place of deposit)** needs a **Place of deposit** of up to 60 characters, for example "Garage", where the driver may leave the parcel without a signature. * **CashService (cash on delivery)** needs a **COD amount** in euro. The **COD reference** is optional. Without one, Zippendo sends the shipment reference. * **AddOnLiabilityService (insurance)** needs an **Insured value** in euro. * **CashService (cash on delivery)** and **AddOnLiabilityService (insurance)** work only on a shipment with one parcel. For several parcels, split the shipment first: see [Split and move parcels](https://www.zippendo.com/docs/how-to/split-and-move-parcels.md). The other products offer fewer services: * **GLS EuroBusinessParcel** takes **FlexDeliveryService** from every country, **DepositService (place of deposit)** from Belgium, and **CashService (cash on delivery)** from Germany to Austria and from Austria to Germany. From Austria, **FlexDeliveryService** does not reach Estonia, Latvia, Lithuania or Sweden. * **GLS ExpressParcel** takes one delivery window: by 08:00 (Germany), 09:00, 10:00 or 12:00, or on Saturday by 10:00 (Germany) or 12:00 (Germany, Belgium). Austria offers 09:00, 10:00 and 12:00, Ireland 12:00, and France only 13:00, which Zippendo adds for you. It also takes **CashService (cash on delivery)** in Germany, Austria and Ireland, and **AddOnLiabilityService (insurance)** in Austria. * **GLS ParcelShop Delivery**, **GLS Parcel Locker Delivery**, **GLS ShopReturn**, **GLS Parcel outside the EU**, **GLS Express outside Europe**, **GLS Pick\&Ship**, **GLS Pick\&Return**, **GLS Shop Returns label** and **GLS Shop Returns QR code** take no services. Zippendo checks these limits before it sends the shipment: | Carrier | COD amount | Insured value | | - | - | - | | GLS Germany | Up to 2,500 EUR | Not offered | | GLS Austria | Up to 2,500 EUR | Up to 3,500 EUR | | GLS Ireland | Up to 1,000 EUR (**GLS ExpressParcel**: 2,500 EUR) | Not offered | Your GLS contract decides which services you can use: GLS refuses a service it does not include when you send. ### Pickups, tracking and customs * **Pickups:** you can ask GLS for a one-time collection under **Pickups**. GLS collects at the address it holds for your **Contact ID** and moves a day it cannot serve to its next working day. Your regular collections stay as your GLS contract sets them. See [Schedule a pickup](https://www.zippendo.com/docs/how-to/schedule-a-pickup.md). * **Tracking:** once Zippendo switches GLS tracking on, GLS sends tracking updates to Zippendo as they happen, also for most shipments you sent in the 14 days before. Until then, each shipment shows the GLS parcel number and a link to GLS's tracking page. Shipments sent with **Test mode** on are not tracked. See [Carrier tracking webhooks](https://www.zippendo.com/docs/how-to/tracking-webhooks.md). * **Customs:** only **GLS Parcel outside the EU** and **GLS Express outside Europe** need customs data. See **Customs outside the EU**. ## Change or remove the connection To change it, open **Carriers** → **My carriers** and click **Edit carrier** on the card. The **Edit carrier** page has two sections: * **General**: **Carrier name**, and **Brand** if your organization has brands. * **Carrier settings**: **Client ID**, **Client secret**, **Contact ID**, **Shop Returns app ID** and **Test mode**. Click **Save**. You see "Carrier updated". When you create a new Client secret for your app on GLS's developer portal, update it here straight away. To remove it, click **Delete** on the same page, type the carrier name in capital letters, and click **Delete**. Shipping rules that use this carrier are deleted with it. Shipments you already sent keep their labels and tracking numbers. ## Common problems | What you see | What to do | | - | - | | "Couldn't connect the carrier. Try again." | Check that every required field has a value, then try again. | | "The carrier rejected your login details. Update the carrier credentials under Carriers." when you send | GLS refused the **Client ID** or **Client secret**, or the app is not enabled for the test or live system you chose with **Test mode**. On **GLS Parcel outside the EU** it also shows when your app is not enabled for GLS's **Customs API**: Zippendo cancelled the parcels, so ask GLS to enable it, then send again. | | "The carrier's settings are incomplete or not valid. Check them under Carriers." | The **Contact ID** has spaces or is longer than 20 characters, or GLS has not enabled your app for this Contact ID. The shipment shows which. Ask your GLS contact to enable the app for your Contact ID. On **GLS Shop Returns label** and **GLS Shop Returns QR code** it also shows without a **Shop Returns app ID**, when your app is not enabled for Shop Returns, or when GLS has not set up returns from your customer's country. | | "GLS doesn't accept this address. Check the address and postal code, then try again." | GLS does not accept the postal code, street or city. Or a name, street, city or second address line is longer than the 40 characters GLS prints: Zippendo stops it rather than cutting it. It also shows for **FlexDeliveryService** without the receiver's email address, and for a ParcelShop or parcel locker delivery with neither an email address nor a phone number for the receiver. The shipment shows the reason. | | "Some options for this carrier product are missing or not valid. Check the shipment's services and options, then try again." | Zippendo checks these before it sends the shipment: cash on delivery without a **COD amount**, insurance without an **Insured value**, an amount above GLS's limit, cash on delivery or insurance on a shipment with more than one parcel, two express delivery windows, a **COD reference** over 160 characters, a **Place of deposit** over 60 characters, a service point in another country than the receiver, or a parcel with no weight or heavier than the product takes. The shipment shows the reason. Nothing was sent to GLS. | | "The customs declaration is incomplete. Each item needs a description, a quantity, and a declared value greater than zero." | On **GLS Parcel outside the EU** or **GLS Express outside Europe**: an order line misses its tariff number, country of origin or value, your EORI number or the receiver's is missing, or the **Incoterm** is one GLS does not take to that country. On **GLS Express outside Europe** also: the sender or receiver misses an email address or phone number, a receiver in the United States or Canada has no state, or the goods are worth more per parcel than GLS takes. If GLS refused the customs data after it created the parcels, the shipment says that Zippendo cancelled them. The shipment shows the reason. Correct it and send again. | | "The carrier accepted the shipment but refused its customs data, so the parcel can't clear customs. Don't hand the parcel over; contact the carrier." | GLS did not confirm the customs data, or could not cancel the parcels after refusing it. The shipment keeps its labels. Contact GLS before you hand the parcel over. | | "GLS couldn't create the shipment." | GLS refused the shipment, for example a service your contract does not include, or a point GLS does not accept. The shipment shows GLS's reason. | | "This product delivers to a service point. Select a service point before sending." | Choose a ParcelShop or parcel locker on the shipment. | | "The selected carrier product does not ship between these countries. Choose a different product." | The product does not cover this route, for example **GLS BusinessParcel** to another country, a sender address outside the carrier's country, a destination outside the EU on any product but **GLS Parcel outside the EU** and **GLS Express outside Europe**, a country in Europe on **GLS Express outside Europe**, a **GLS Shop Returns QR code** from a country GLS issues no QR code in, or Northern Ireland. It also shows for a service the product does not offer on that route, for example cash on delivery from Germany to France. | | "The connection to the carrier was lost before it answered. Zippendo has no confirmation that the shipment was created, so check with the carrier before sending again." | GLS did not confirm the shipment: the connection dropped, or GLS answered with an error after it may have created it. Look up the shipment's reference in your GLS portal before you send it again. | | "The carrier did not respond. Try again in a moment." | GLS's sign-in did not answer, so nothing was booked, or GLS did not answer while Zippendo searched for service points. Try again in a moment. | More help: [Carrier authentication failures](https://www.zippendo.com/docs/knowledge-base/carrier-authentication-failures.md). ## Related * [Connect GLS Denmark](https://www.zippendo.com/docs/how-to/connect-gls.md) * [Connect GLS (MyGLS)](https://www.zippendo.com/docs/how-to/connect-gls-mygls.md) * [Connect GLS Netherlands](https://www.zippendo.com/docs/how-to/connect-gls-netherlands.md) * [Connect a carrier or integration](https://www.zippendo.com/docs/how-to/connect-index.md) * [Carrier credentials](https://www.zippendo.com/docs/how-to/carrier-credentials.md) * [Test mode](https://www.zippendo.com/docs/how-to/sandbox-mode.md) * [Carrier products and services](https://www.zippendo.com/docs/how-to/carrier-products-and-services.md) * [Pick a service point](https://www.zippendo.com/docs/how-to/pick-a-service-point.md) * [Inbound and returns](https://www.zippendo.com/docs/how-to/inbound-and-returns.md) This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.