Microsoft 365 MFA - I have lost my mobile which has Microsoft Authenticator apps installed now how to login and register to another mobile .

 1) Update your Office 365 Admin to revoke MFA Session and Require Re-Register MFA.

Go to Azure AD > User (select user) > Authentication methods > Click on Require re-register MFA  and Revoke MFA Session.

2) Go to the URL :  https://aka.ms/proofup and setup your new device.

3) Once Device is get setup you can able to see your old device , Remove this .