Controlling data sharing, visibility, and access permissions within Microsoft Teams for Education
Hi 22,
Have you tried to clear the cache?
Refer to the link below for the steps to clear the cache.
https://learn.microsoft.com/en-us/microsoftteam...
I suggest to use or log in your personal account as the school account might have a restrictions set by the administrator or IT.
Link below might help you to solve the issue and provide steps on how to troubleshoot the account doesn't exist.
https://answers.microsoft.com/en-us/msteams/for...
Please let me know if this doesn't work or if you need further assistance.
Thank you.