Probability score: 0.6  

Question improvement suggestion: Please provide the exact error message you are receiving when trying to authenticate with the Deepl API, as well as any troubleshooting steps you have already taken.  

In the meantime, based on the information you have provided, here is a suggested answer to your question:  

Hello Paraskevas,  

Thank you for reaching out regarding the authentication issue with the Deepl API in Trados Studio 2021. Let's work through some steps to help you resolve this problem.  

**Step 1:** Verify your API Key  

- Ensure that the API key you are using is correct. You can log in to your Deepl account to check if the key is valid and has not expired. If necessary, generate a new API key and try again.  

**Step 2:** Update Trados Studio and the Plugin  

- Make sure that you have the latest version of Trados Studio 2021 installed. You can check for updates by going to Help > Check for updates.  

- Uninstall the current Deepl Translation Provider plugin from Add-Ins > RWS AppStore > Installed plug-ins, and then reinstall the latest version from the RWS AppStore.  

**Step 3:** Check Network Settings  

- Ensure that there are no firewalls or network configurations blocking the connection to the Deepl API.  

- If you are using a proxy, you may need to configure it in the SDLTrados Studio.exe.config file as mentioned in previous discussions.  

**Step 4:** Clear Studio Settings  

- If the issue persists, consider resetting your Trados Studio settings. You can do this by renaming the Studio16 folder located in C:\Users\%USERNAME%\AppData\Roaming\SDL\SDL Trados Studio\Studio16. This will reset your settings and may resolve any conflicts.  

**Step 5:** Confirm Language Support  

- Check that the languages you are working with are supported by Deepl. Certain languages may have restrictions or may not be available for translation.  

If you continue to experience issues, please provide the exact error message you are receiving, as this will help in diagnosing the problem further.  

I hope this answer addressed your question. If not, please reject the answer, add the question improvement suggestion information, and click the RWS Community AI checkbox on the right to try again.  

RWS Community AI

Hi Paraskevas Stavrakos

This topic actually has been discussed a lot in this forum already. Unfortunately, with the changes implemented by DeepL to the API authentication methods, this app no longer works for Trados 2021.

From 28 February 2026, DeepL discontinued support for outdated authentication methods used by older versions of CAT tools. For further details, please see: https://developers.deepl.com/docs/resources/breaking-changes-change-notices/november-2025-deprecation-of-legacy-auth-methods

The Trados AppStore Team implemented support for the new authentication methods from DeepL starting from Trados Studio 2022 (i.e. Trados Studio 2022, 2024 & 2026 ...). This means that the DeepL Translation Provider will no longer work in Trados Studio 2021 and earlier versions, which are versions that are no longer supported technically and by engineering.

You can read the full article from our technical support team here:

https://gateway.rws.com/csm?id=kb_article_view&sysparm_article=KB0011924

And this is from DeepL's website:

https://support.deepl.com/hc/en-us/articles/360020678680-DeepL-for-Trados-Studio

Perhaps you can consider upgrading to Trados 2024 or starting a subscription plan for Trados 2024.

Best regards,

Anca

Hi Anca,

Thank for the reply. I didn't know it was a marketing issue. 

I will cinsider upgrading to 2024 version.

Best

Paraskevas