Azure AD B2C MFA saves phone number with incorrect format (without space)

s k 6 Reputation points

Currently we trying to reset MFA in Azure B2C through Microsoft Graph API. The idea is to delete existing phone number in authentication methods, that at the next login user would be prompt for provide new one. We are using standard built-in user-flows for user login / registration.

The problem is that B2C during MFA registration stores phone number in authentication methods without space between country prefix and phone number (so in Azure Portal it’s +11112223333, and should be +1 1112223333). MFA works fine, but because of this:

  1. we are not able to query for phone number with Graph Api ( ) – GET returns empty array;
  2. we are not able to delete phone number with Graph Api ( – DELETE returns 404;

One workaround is POST new fake number with correct format through Graph Api and then delete it. Do you know is there better way to reset MFA or force B2C MFA to store phone number in correct format?

Microsoft Entra ID
Microsoft Entra ID
A Microsoft Entra identity service that provides identity management and access control capabilities. Replaces Azure Active Directory.
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  1. Martín Fernández 6 Reputation points

    I don't think that the space is related to this problem. I was able to hardcode a phone number when persisting it to the strongAuthenticationPhoneNumber attribute and it doesn't show up in the API either way.

    1 person found this answer helpful.

  2. James Hamil 23,216 Reputation points Microsoft Employee

    Hi @s k , we have an issue ticket raised for this that we are working on. When it is finished we will let you know, hopefuly soon!


  3. Hetal Madhani 1 Reputation point

    Is there any update on this? We are experiencing the same issue.

  4. Tomas Salim 1 Reputation point

    Is there any update about this? Any ticket we can track?

    0 comments No comments

  5. apparao 1 Reputation point

    Hi All,

    I am unable to save the MFA phone number without space in azure portal via custom policy ,can anyone provide the update on this ?

    0 comments No comments