Cannot log into Microsoft 365 on one laptop: Authenticator push notifications and verification codes stopped working, but account works fine elsewhere

Hello Microsoft Support Community,

I am facing a frustrating issue trying to sign in to my Microsoft 365 account on one of my laptops.

Here are the details of the situation:

The Account: My Microsoft 365 account is fully functional and I can still sign in normally on my other laptop and another mobile device.

The Problem: When trying to log in on my main laptop, it requires approval via the Microsoft Authenticator app. However, push notifications are not arriving at all.

Missing Alternatives: I do not have any alternative sign-in methods set up (like SMS or alternate email) on this account.

The Authenticator Issue: Even the 6-digit rolling verification codes inside the Microsoft Authenticator app are not showing up or working for this account, despite the app working fine just a couple of days ago.

The Barrier: Because I cannot access this account on this specific laptop, I am blocked from reaching standard support channels that require login authentication.

Could someone please advise on how I can regain access or get manual assistance from Microsoft support to verify my identity and bypass or reset the Authenticator requirement for this device?

Thank you in advance for your help!