Accessing Microsoft Teams for Education using school or organizational credentials
Dear @Deepika Karra,
Based on your description, your Authenticator app does not work so you cannot sign your account.
In this situation, the only effective solution is contact to your IT/admin of your school, since your account is a education account, your school IT team or Helpdesk may be able to reset your Multi-Factor Authentication (MFA) settings. As a forum user, I do not have administrative access to change these settings. Only your school IT team has the ability to adjust or reset your MFA configuration.
You can also refer to this Microsoft support article for more information: Manage authentication methods - Microsoft Entra ID | Microsoft Learn
I hope information above can help you resolve the issue as soon as possible, please feel free to reach out if you have any other questions.
Note: Please follow the steps in the forum documentation to enable e-mail notifications if you want to receive the related email notification for this thread.