@Gina ,
What changes do you do before this issue happened?
Does anyone else have the same issue?
To exclude the account side issue, try to join Teams meeting in Teams web client(https://teams.microsoft.com) and observe the result.
If it can work properly from web client, perform a clean boot to avoid the conflict with other applications.
Moreover, it recommends you contact IT admin to check if there is any related error message in Health status of Microsoft Teams from Microsoft 365 admin center > Health > Service health.
If there is any related error message, please make a screenshot for us to know more about your situation.
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