Do you mean you cannot change another account to login Teams application, right?
Can you use your Microsoft Account to login other applications such as outlook?
If this issue only persist on Teams application, we recommend you try to clear cache file of Microsoft Teams app by following these steps:
If you are using Teams app on your computer, try to clear cache of Microsoft Teams app by following these steps:
- Sign out from Teams app
- Quit Teams app from the System tray
- Cut and paste the following location into File Explorer: %appdata%\Microsoft\Teams
- Delete contents of the entire folder.
- Open your Teams app then sign in with your personal account
But if you are using Teams web version, you may try to use in-Private browser or try to clear cache the web browser you are using.
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