How to integrate and configure Azure AD B2C Custom Policy to send MFA SMS step by step?

Question

How to integrate and configure Azure AD B2C Custom Policy to send MFA SMS step by step?

Palani Gangadurai 0

Hi, I am looking for a detailed, step-by-step guide to integrate and configure Multi-Factor Authentication (MFA) using SMS in Azure AD B2C with Custom Policies. I need help understanding how to:

Define the phoneNumber claim type with proper validation (E.164 format).
Collect the phone number input using a SelfAsserted technical profile.
Configure the PhoneFactor technical profile correctly.
Add the necessary orchestration steps.
Ensure proper session management and claim transformations (like userIdForMFA if needed).

I tried to integrate the below Twillio integration documents for sending a custom SMS in Azure AD B2C Custom Policy:

Guidelines: Twilio Verify App with Azure Active Directory B2C - Azure AD B2C | Microsoft Learn

Azure Custom Policy XML code sample: samples/policies/twilio-mfa-psd2/policy/SignUpSignIn at master · azure-ad-b2c/samples

Regards,

Palani

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Answer 1

Kancharla Saiteja 5,810 Microsoft External Staff Moderator

Hi @Palani Gangadurai,

Based on your query, here is my understanding: You would like to configure MFA in your Azure AD B2C using custom policies.

I see you would like to have custom MFA in your tenant to which you have chosen the right way by using the mentioned documents: Integrating Twilio Verify App with Azure Active Directory B2C. Twilio helps in customization of MFA and can set as per your requirement. I believe you have configured these policies using this document: twilio-mfa-psd2. Please make sure you have configured all the policies including TrustFrameworkExtensionsPSD2.xml and TrustFrameworkExtensionsPSD2StepUp.xml, which make sure your claims have properly configured.

TrustFrameworkExtensionsPSD2.xml defines the claims, claims transformation and strong authentication as well. Once you configure these parameters here, then you can update the setup in TrustFrameworkExtensionsPSD2StepUp.xml. This configuration will help you in operating custom MFA successfully.

If you would like to go with Azure AD B2C standard MFA, please go through this document: Enable multifactor authentication in Azure Active Directory B2C.

Here is the sample to configure MFA with TOTP: Azure AD B2C MFA with TOTP using any Authenticator app

I hope this information is helpful. Please feel free to reach out if you have any further questions.

If the answer is helpful, please click "Accept Answer" and kindly "upvote it". If you have extra questions about this answer, please click "Comment"

Kancharla Saiteja 5,810 Reputation points Microsoft External Staff Moderator

2025-04-08T16:55:11.45+00:00

Hi @Palani Gangadurai,

Following up to see if the above answer was helpful. If this answers your query, do click Accept Answer and Yes for was this answer helpful. And, if you have any further query do let us know
Kancharla Saiteja 5,810 Reputation points Microsoft External Staff Moderator

2025-04-09T16:46:35.89+00:00

Hi @Palani Gangadurai,

Following up to see if the above answer was helpful. If this answers your query, do click Accept Answer and Yes for was this answer helpful. And, if you have any further query do let us know
Palani Gangadurai 0 Reputation points

2025-04-09T18:05:45.1166667+00:00

Hi @Kancharla Saiteja

Thank you for your response.

We have already tried the sample code provided at: https://github.com/azure-ad-b2c/samples/tree/master/policies/twilio-mfa-psd2

We have configured all the policies, including TrustFrameworkExtensionsPSD2.xml and TrustFrameworkExtensionsPSD2StepUp.xml. However, we are unable to achieve custom SMS functionality in MFA. We are currently facing the following two issues:

Azure MFA does not allow enforcement of custom policy SMS – We continue to receive the default Azure SMS instead of the expected custom message.

Custom policy changes are not enforced during sign-in – When attempting to sign in to the Azure AD B2C application, the custom policy appears to be ignored.

Additionally, we are encountering the following error during sign-up:

Error: The page cannot be displayed because an internal server error has occurred.

This error occurs specifically at the MFA stage when signing up a new user.

Would you be able to review the custom policy XML files if we share them with you? We’ve been facing this issue for the past 15 days and would appreciate your support.

For reference, we were able to successfully configure custom email delivery via Twilio-SendGrid, following this documentation: https://learn.microsoft.com/en-us/azure/active-directory-b2c/custom-email-sendgrid?pivots=b2c-custom-policy

Looking forward to your assistance.

Best regards,
Palani
Kancharla Saiteja 5,810 Reputation points Microsoft External Staff Moderator

2025-04-09T18:15:47.2966667+00:00

Hi @Palani Gangadurai,

Thanks for your response,

Could you please share your custom policies and error screenshot you are receiving for the new user. Also please share your customized expectation message you would like to receive for your MFA. I have initiated private message, kindly share this information in it.
Palani Gangadurai 0 Reputation points

2025-04-10T07:26:39.6933333+00:00

Hi @Kancharla Saiteja

Thank you for the quick response.

I have provided all the information about custom policies xml files and error screen shots in the private message.

Kindly review them and share your valuable feedback to help us resolve this long-pending issue.

Best regards,

Palani G.
Kancharla Saiteja 5,810 Reputation points Microsoft External Staff Moderator

2025-04-10T17:57:57.16+00:00

Hi @Palani Gangadurai,

Thank you for your information,

Let me check the provided information and update you accordingly.
Kancharla Saiteja 5,810 Reputation points Microsoft External Staff Moderator

2025-04-12T00:39:11.9966667+00:00

Hi @Palani Gangadurai,

We are checking the required information from our end which is taking a bit of time. Kindly allow us sometime to identify the issue and update you accordingly.
Palani Gangadurai 0 Reputation points

2025-04-13T20:00:17.0166667+00:00

Hi @Kancharla Saiteja

Thank you for investigating this issue. We look forward to your next update.

Regards,

Palani
Kancharla Saiteja 5,810 Reputation points Microsoft External Staff Moderator

2025-04-23T16:56:15.7633333+00:00

Hi @Palani Gangadurai,

Following up to see if the above answer was helpful. If this answers your query, do click Accept Answer and Yes for was this answer helpful. And, if you have any further query do let us know
Kancharla Saiteja 5,810 Reputation points Microsoft External Staff Moderator

2025-04-24T16:32:25.0033333+00:00

Hi @Palani Gangadurai,

Following up to see if the above answer was helpful. If this answers your query, do click Accept Answer and Yes for was this answer helpful. And, if you have any further query do let us know
Palani Gangadurai 0 Reputation points

2025-05-14T10:50:32.9233333+00:00

Hi @Kancharla Saiteja

Thank you for investigating this issue. We look forward to your next update.

Could you please help us close this issue at the earliest? Our client is actively following up on the deployment.

Regards,

Palani

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How to integrate and configure Azure AD B2C Custom Policy to send MFA SMS step by step?

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