I have the same problem.
I did reinstalling of the trados studio and removing of "base settings", "Usersettings", and "plugincahce".
However, the problem didn't solved.

Hello @정 철우   Arya Hajiali Larijani Sandor Juhasz Lydia Chessum Anna Moorby

Can i confirm whether you have installed SDL Machine Translation cloud please?

You may also find the following article useful-

https://gateway.rws.com/csm?id=kb_article_view&sysparm_article=KB0037207

Hi there 

I have downloaded the plugin today as a temporary replacement but would be good to find out what’s happening with language cloud too.

thanks 

Hello.
when I use "SDL Machine Translation Cloud", machine translation is worked well.
However, when I use "SDL Language Cloud", the problem I mentioned above occurs.
I mainly use "SDL language Cloud" because I use "translation engine" in which the translation memory what I made and the machine translation provided by SDL are included.
Additionally, I checked the article you mentioned and I tested 'pre-translate' in the batch task menu.  In this case, the machine translation was worked well.
However, using the machine translation for each segment is still not worked.

Hello.
when I use "SDL Machine Translation Cloud", machine translation is worked well.
However, when I use "SDL Language Cloud", the problem I mentioned above occurs.
I mainly use "SDL language Cloud" because I use "translation engine" in which the translation memory what I made and the machine translation provided by SDL are included.
Additionally, I checked the article you mentioned and I tested 'pre-translate' in the batch task menu.  In this case, the machine translation was worked well.
However, using the machine translation for each segment is still not worked.