Since reinstalling Teams can temporarily fix this issue, you can try to sign out and kill Teams from Task Manager to see how it goes.
If the problem persists, you can try to clear Teams cache to see if it can help:
1. Fully exit the Microsoft Teams desktop client. You can right-click Teams from the Icon Tray and select ‘Quit’ or run Task Manager and fully kill the process.
2. Go to File Explorer, and type in %appdata%\Microsoft\teams.
3. Once in the directory, you’ll see a few of the following folders:
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a. From within ‘Application Cache’, go to Cache and delete any of the files in the Cache location.
* %appdata%\Microsoft\teams\application cache\cache
b. From within ‘Blob_storage’, delete any files that are located in here if any.
* %appdata%\Microsoft\teams\blob_storage
c. From within ‘Cache’, delete all files.
* %appdata%\Microsoft\teams\Cache
d. From within ‘databases’, delete all files.
* %appdata%\Microsoft\teams\databases
e. From within ‘GPUCache’, delete all files.
* %appdata%\Microsoft\teams\GPUcache
f. From within ‘IndexedDB’, delete the .db file.
* %appdata%\Microsoft\teams\IndexedDB
g. From within ‘Local Storage’, delete all files.
* %appdata%\Microsoft\teams\Local Storage
h. Lastly, from within ‘tmp’, delete any file.
* %appdata%\Microsoft\teams\tmp
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Once the cleanup is finally completed, you can now restart Teams and check the results.
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Another Solution:
In Windows 10 > Settings > Accounts > Access work or school, find the account you're attempting to use to sign into Teams. If it's not here add it. If it is here, disconnect and then reconnect your account.
