Authenticator Issue - Request code not shown - 8 vs 6 digit codes

Please note that I have a personal Gmail account that I use to access Microsoft services.

Some contacts share folders with me through SharePoint. Whenever I receive one of these sharing invitations and try to access the folder, I am asked to authenticate my Microsoft account.

Unfortunately, I am getting stuck in an authentication loop and cannot complete the sign-in process.

It appears that Microsoft is sending an authentication request to my Microsoft Authenticator app, but the notification never arrives on my phone. I have checked the app, but there is no pending authentication request.

The alternative option is to enter a verification code. However, there seems to be a mismatch: the SharePoint/Microsoft sign-in page asks me for a 6-digit code, while Microsoft Authenticator is generating 8-digit codes for my account. Therefore, the code generated by the app is not accepted. I have read this has to do with personal vs corporate accounts, but I only own a personal account.

Could you please advise me on how to resolve this issue? In particular, I would like to know:

1. Why the Authenticator approval notification is not reaching my phone.
2. Why my Authenticator app is generating 8-digit codes when Microsoft is asking for a 6-digit code.

I would appreciate any guidance on how to get out of this authentication loop and regain access to the shared folders.