Hello Jessie,
Good day! Thank you for reaching out.
I'm sorry to hear that you're having trouble with the Authenticator app. Since we have dedicated support team for Microsoft Authenticator related queries, I'd also recommend you to kindly also post your query to Microsoft Authenticator support Forum via Microsoft Authenticator - Microsoft Q&A Engineers who are dedicated into Microsoft Authenticator with rich experience and more resources can then assist efficiently.
Also, you may contact your school's M365/IT administrator to reset MFA for you through the Azure admin portal. In the Azure portal, the administrator can set your account to Require new MFA registration. This disables all previous authentication methods, removes the app and you will then be prompted to configure a new MFA authentication method the next time you sign in so that you can do the set up afresh. The admin can also add another authentication method for you like phone/SMS in this portal so that you have more than one option.
If you need guidance on how to find your admin, please refer to How do I find my Microsoft 365 admin? - Microsoft Support
More info at: Manage authentication methods for Azure AD Multi-Factor Authentication - Microsoft Sign In | Learn with Microsoft
Thanks for your precious time and your understanding would be highly appreciated.
Have a nice day!
Best Regards,
Ashraf.