You want to open a server or file-based termbase in MultiTerm, but as soon as you click on "Open termbase", you get the following error message: 

A connection to SDL MultiTerm Server unknown could not be established
 

Resolution 1 :

1. Go to C:\Users\%UserName%\AppData\Roaming\SDL\SDL MultiTerm\
2. Rename:

• For Multiterm 2021 rename the  MultiTerm16 folder to MultiTerm16_OLD
• For Multiterm 2019 rename the  MultiTerm15 folder to MultiTerm15_OLD
• For Multiterm 2017 rename the  MultiTerm14 folder to MultiTerm14_OLD

NOTE: for Multiterm 2022 go to C:\Users\%UserName%\AppData\Roaming\Trados\MultiTerm\ and rename the folder MultiTerm17 to  MultiTerm17_OLD.

3. Go to Control Panel\All Control Panel Items\Programs and Features and right-click on the SDL MultiTerm 2017/ 2019/ 2021/2022 Desktop and select Repair.

Resolution 2 : 

Install the latest version of Multiterm 2022/2021/2019/2017.
 

If you cannot see the files and folder paths mentioned in this article, it is likely that Windows Explorer is not configured to show hidden files and folders. Please refer to following KB article to find out how to show hidden files and folders:

• Showing hidden files, folders and extensions on Windows operating systems

Resolution 3 :

If you are connected to a VPN, please check if the error still occurs after disconnecting from it.

We have encountered for example cases where this error was caused by NordVPN or ExpressVPN.

We have also encountered the issue on a machine where the SentinelOne Endpoint Agent was installed.

For further information, please see: "A connection to SDL MultiTerm Server unknown cloud not be established" error message appears while trying to open a termbase.
 

Corrupted MultiTerm settings, or 3rd party application interfering with the correct functioning of MultiTerm.