Azure B2C: Unblock phone number- Phone number has bad reputation, blocking

Johannes 0 Reputation points
2023-06-07T09:20:23.1066667+00:00

Dear Azure-Community-Team,

 

I found this post in the Q&A section:

https://learn.microsoft.com/en-us/answers/questions/1160845/azure-b2c-unblock-phone-number-phone-number-has-ba

 

We’re currently facing similar logon issues in our Azure AD B2C tenant with certain customers, which are related to the phone numbers they are using for MFA via phone call or SMS.

The audit log shows the same error message as in the above mentioned post “Phone number has bad reputation, blocking.”.

The affected phone numbers start with country code "+38" and "+77".

Anything we can do about it?

Thank you and best regards
Johannes

Microsoft Security | Microsoft Entra | Microsoft Entra ID
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  1. James Hamil 27,221 Reputation points Microsoft Employee Moderator
    2023-06-07T20:55:16.3366667+00:00

    Hi @Johannes , I'm sorry you're having this issue. I answered a post similar to this as well a few weeks ago. The current solution for this is to use the Authenticator app or verification code instead of a phone number. If you absolutely need to use a phone number there are 2 steps for you to follow:

    1. Send me an email at "azcommunity@microsoft.com" with subject "ATTN: James Hamil" and your subscription ID.
    2. Contact the phone providers of the numbers having issues, and ask if they are flagged for some reason. Historically these issues have been caused by the phone providers, not Microsoft.

    Please let me know if you have any questions and I can help you further.

    If this answer helps you please mark "Accept Answer" so other users can reference it.

    Thank you,

    James


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