Trados 2021 bug: concordances not working anymore

Hello,

The concordances search is not working anymore in Studio 2021. I tried it with different projects for different clients. It works for some of them and not for some others. I tried with F3 and from the menu (the "Search concordances" option is active, but when I try to use it "Searching..." appears and nothing happens).

I recently updated to SR 1 16.1.5.4270, but it is possible (not sure) that the problem was already there before.

Could you please help? This is a big problem!

Thanks in advance