Microsoft Authenticator does not receive authorization requests when signing into Azure. It works on Microsoft 365.

I have an org account that is also a Global Administrator in Entra ID. When the user signs on he is asked to authenticate using Microsoft Authenticator but the phone never receives the message. The user is able to sign in to Microsoft 365 and Dev Ops. There is one Authenticator that shows in the user's profile. It was created by the user at https://mysignins.microsoft.com/security-info The authenticator is shown in the user's Authentication Methods section in Entra ID.

The user recently changed phones. It's almost as if Azure is expecting the other phone to respond. We can't test that because he wiped the phone when he traded it in.

How can I get him signed into Azure AD?

In addition, I tried having him remove the Authenticator. Azure's login process is still asking for an Authenticator response.