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

Question

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

Johannes 0

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

Shweta Mathur 30,301 Reputation points Microsoft Employee Moderator

2023-06-14T04:26:33.1833333+00:00

Hi @Johannes ,

Just checking in to see if the below answer helped. If this answers your query, please don’t forget to click "Accept Answer" which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.

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Shweta Mathur 30,301 Reputation points Microsoft Employee Moderator

2023-06-14T04:26:33.1833333+00:00

Hi @Johannes ,

Just checking in to see if the below answer helped. If this answers your query, please don’t forget to click "Accept Answer" which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.

Answer 1

James Hamil 27,221 Microsoft Employee Moderator

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:

Send me an email at "azcommunity@microsoft.com" with subject "ATTN: James Hamil" and your subscription ID.
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

Johannes 0 Reputation points

2023-06-12T14:29:23.5233333+00:00

Hi James,

switching to the Authenticator app would be our preferred option as well, but the problem with that is, that Azure B2C only allows configuring phone/SMS OR Authenticator app via radio buttons, but not both at the same time - at least not via GUI - and we still need phone/SMS in certain areas. I'm aware of the Identity Experience Framework, which allows for more sophisticated configuration, but it requires way deeper technical knowledge.

Thanks and best regards
Johannes

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

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