Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hi Christophe
Thank you for reaching out to the Microsoft Community.
I understand you're unable to approve Microsoft Authenticator sign-in requests after switching to a new phone and no notification appears in the app.
Since this is a work or school account, please contact your Microsoft 365 administrator and ask them to reset your MFA methods. Once the reset is completed, you should be able to sign in again and re-register Microsoft Authenticator on your new device.
If you are the only administrator for your organization, please let me know, and I can provide the next steps to recover access and contact the appropriate Microsoft support team.
As a Community Moderator, I do not have access to your organization's tenant and cannot reset MFA methods or modify authentication settings.
I hope this helps. Please let me know if you have any questions.
Warm regards,