Are there any error messages when login in Teams for Linux?
I tested in Ubuntu 20.04 with Microsoft Teams version 1.4.00.7556(64-bit) and it can login normally.
In this case, we recommend you check if you can login in Teams web client normally. If there is no issue, then you could try to clear your client cache as below:
rm -r ~/.config/Microsoft/Microsoft\ Teams\ -\ Insiders
If all the suggestions are no help, I want to confirm more questions with you:
1.What changes do you do before this problem happened?
2.Does anyone else have the same problem?
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