This worked for me:
Delete:
%LocalAppData%\Packages\MSTeams_8wekyb3d8bbwe
%LocalAppData%\Packages\Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy
%LocalAppData%\Microsoft\OneAuth
%LocalAppData%\Microsoft\TokenBroker
%LocalAppData%\Microsoft\IdentityCache
Then restart the PC