Dear @Christo Jose Tom
Thank you for reaching out to Microsoft Q&A Forum.
We understand you're having trouble with your Authenticator because you lost your phone.
Assume if your email, which is from work or school, its security settings, including MFA, are managed by IT department. As forum moderators, we don’t have access to the detailed system needed to troubleshoot this effectively due to privacy and security constraints.
To quickly resolve this and regain access, the most effective step is to contact IT Support or Help Desk directly. Only they have the ability to adjust your MFA settings, reset them, or help you set up a new verification method.
We suggest you contact your Global Administrator to ask them to follow this article to proceed to reset your 2FA so that you could re-register again: Manage authentication methods for Microsoft Entra multifactor authentication - Microsoft Entra ID | Microsoft Learn
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