Authenticator notification not received when using B2B to sign in to business partner Teams team

Question

I have a user using his id of our tenant to do a B2B sign in to business partner's Teams team in their tenant. He is prompted to sign in, successfully provides his email address and password from our tenant, then successfully fulfills an MFA notification branded as our tenant, the receives a MFA prompt branded as the business partner's tenant, but the corresponding Authenticator notification from that tenant never arrives to his MS Authenticator.

The user recently replaced his iPhone, so I suspect the business partner branded MFA notification is trying to go to that old Authenticator instance. However, I have no way to validate or resolve this. I did speak with an administrator from the business partner and have him look at the authentication settings of the guest account; when he looked there were no authentication settings configured for that guest account.

What is the best way to resolve this?

Answer 1

Hello Kurt Bestul,

Thanks for your question.

I understand he replaced his phone, if he did not backup his authenticator settings then the account MFA has to be re-registered as there is no alternative.

Removing the old device from their Microsoft Authenticator settings in both their tenant and the business partner’s tenant (if applicable).

Here are the steps:

• Sign in to the Azure portal.
• On the left, select Entra > Users > All users.
• Choose your account->select Authentication methods and click "Require re-registration for MFA".

You can mark it 'Accept Answer' and 'Upvote' if this helped you

Regards,

Abiola