Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Thank you for reaching out to the Microsoft Q&A Forum and sharing your issue.
Based on your description, I understand that you are unable to sign in to Outlook using your school account because Microsoft Authenticator is not providing a verification code and the sign-in process keeps redirecting you back to the Authenticator app.
Since this is a school account managed by your organization, the best option would be to contact your IT administrator and ask them to follow this article to reset MFA for you: Manage authentication methods for Microsoft Entra multifactor authentication - Microsoft Entra ID |…. After that, you should be able to register your phone again from scratch.
For security and management reasons, only your organization’s IT administrators can manage access and MFA settings for school accounts. Microsoft Support cannot directly reset MFA for accounts that are managed by an organization.
Once you regain access, it's a good idea to set up an additional sign-in method if your organization allows it (such as phone or email), so you’ll have a backup option in case something like this happens again.
I hope this information helps.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.