When entering credentials in Trados Studio to connect to WorldServer to upload a Return package, the following error occurs:

The connection to server xxxx could not be established for the reason: (Response is not well-formed XML​)



This happens after WorldServer has been upgraded from version 10.4.x to version 11.0 or higher even if the connection worked before.
 

To permanently fix this issue, the url_of_origin in the general.properties file needs to be updated to change from '<url>/ws' to '<url>/ws-legacy'. On the server where WorldServer is installed, find the general.properties file. Open it and update the Server Address next to the url_of_original property to change from:
 

url_of_origin=https://xxxxxx.sdlproducts.com:###/ws/

to

url_of_origin=https://xxxxxx.sdlproducts.com:###/ws-legacy/

Finally, restart WorldServer. The URL in SDL Trados Studio will now be the legacy one.

A workaround before making the change in general.properties is to manually change the address in SDL Trados Studio to include ws-legacy:



Note: your URL will be different from the ones pictured. The important thing to note is where /ws/ occurs in the URL and update only this portion with /ws-legacy/.


 

The Server Address needs to be updated in the general.properties file. The url_of_origin value in the general.properties file was not changed during the upgrade.

This article might be useful:

Configuring .properties files starting from WorldServer 11