We can log into MultiTrans Flow via Trados Studio successfully but when we try to open a job, the message Language mapping not found appears:

1. Log into the Administration Console then navigate to Servers > (your server URL) > TextBases and Team Server. Select each TextBase attached to the project in Flow then click Properties and make a note of all the languages listed:

NOTE: If any of the languages have the name "???" in the properties window, please read the following article first:
MultiTrans - TextBase contains a language with the name "???" in the Administration Console

2. Go to Security > Languages then for each language noted, click Edit and make sure it has a value selected in the Trados Code field:

3. Try to download the project in Studio again. If you still get the same error, continue with the extra steps below.

Extra steps if you still get the same error:

Requires access to the server.

There may be some languages in the project TextBases which are not shown in the TextBase's properties in the Administration Console. You can find these "hidden" languages by searching the log files on the server.

4. Look for the following log file on the server and open it in Notepad:
C:\ProgramData\Donnelley\Tracing\MultiTrans.Services.Host.Api.log

5. Search for the text highlighted in red below around the same time that you attempted to open the project in Studio.
 

[Error] [Package Manager Service - Generate Package, General] [ 108] ProjectId: 1234, ProjectName: TEST-210101-001, TaskId: 5555. Package Manager Service - Generate Package. Input: 

On this line, the list of language codes (highlighted in green) will be listed for each TextBase attached to the Flow project. Make a note of them:

"TextBases":[{"Name":"Demo TextBase","Id":12345,"IsOnline":true,"Languages":["fr-FR","en-GB","ar-SA","bg-BG"],"Type":0}],"TermBases":[]}

In the example above, there is one TextBase called "Demo TextBase" with four languages: "fr-FR" (French), "en-GB" (English), "ar-SA" (Arabic) and "bg-BG" (Bulgarian).

To make this error easier to read, select Format > Word Wrap in Notepad:


6. Repeat step 2 for every language listed in the log file.

There are languages included in the project's TextBases that do not have a Trados Code assigned to them in the Administration Console. The language codes used by MultiTrans and Trados Studio may differ, so they need to be mapped explicitly. For more information, see the links in the Reference section.