Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
I saw that you choose Education tag, can you please confirm if you are using your school/university account?
Can you still log in via https://mysignins.microsoft.com/security-info by using any alternative method (phone/ sms, etc.)? If yes, try removing your old Authenticator method and then register again.
If no alternative method is available, since this is a school account and you are completely locked out, the quickest way is to contact your school’s IT support team or system administrator. They can reset your authentication settings for you and guide you through setting up the Authenticator app again on your new device.
Please ask them to follow the instructions in this article to reset your authentication settings so you can re-register your account: Manage authentication methods for Microsoft Entra multifactor authentication - Microsoft Entra ID |…
Note: 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 institution.
I hope this information helps.
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