How to reset 2FA device?

IT Admin 6

Under my azure account, I have 2 subscriptions. One has administrators (Sub A), but the other one (Sub B)is only I am the administrator.

Now, I replaced my phone, and I lost connectivity with MS Authendicator.

One subscription which has other administrators, I could reset from one of the administrator.

But the other sub B I could not find any solution.

Could you help the login issue?

Your answer