Styra inställningar, behörigheter och medlemskap i Teams och kanaler
If you don't have permission to edit the user status, you would need to contact the admin to do the process.
They could also try running the guest access test in the admin center, or remove the guest and then re-add them.
For information on setting up guest access, you may see the link:
https://docs.microsoft.com/en-us/MicrosoftTeams...
Thank you for your patience.