API Management Developer Portal Sign-Up Fails with Server Error — Assistance Needed

Question

API Management Developer Portal Sign-Up Fails with Server Error — Assistance Needed

Ryan Suarez 40

Problem description

We've configured Secure access to API Management developer portal using Microsoft Entra Authentcation. User is able to login to entra successfully and is then redirected to Complete sign up page.

After entering the email address the error 'Server error. Unable to send request. Please try again later.' is presented.

Developer Tools is showing the following response...

Request URL: https://[myapim].data.azure-api.net/users?api-version=2022-04-01-preview Request Method: POST Status Code: 400 Bad Request (from service worker) { 'error': { 'code': 'ValidationError', 'message': 'User registration is not supported.', 'details': null } }

Environment

Azure API Management Service, Entra ID Authentication, Microsoft.ApiManagement/service, Canada Central Region

Any insight would be greatly appreciated.

Ryan Suarez 40 Reputation points

2026-09-15T16:19:30.9866667+00:00
Hi @Tejaswini Billakurthi

Thank you for the prompt response.

Confirmed, the Username and password provider was removed. Microsoft Entra ID is the only one configured.

Our APIM SKU is Standard v2, East US 2 region. It was previously configured for Azure AD B2C. Since this was deprecated we deleted it and configured EntraID. No users can currently login since there are no existing EntraID users, everyone is essentially a new user.

Answer accepted by question author

0 additional answers

Your answer

Ryan Suarez 40 Reputation points

2026-09-15T16:19:30.9866667+00:00

Hi @Tejaswini Billakurthi

Thank you for the prompt response.

Confirmed, the Username and password provider was removed. Microsoft Entra ID is the only one configured.

Our APIM SKU is Standard v2, East US 2 region. It was previously configured for Azure AD B2C. Since this was deprecated we deleted it and configured EntraID. No users can currently login since there are no existing EntraID users, everyone is essentially a new user.

Answer 1

Hi @Ryan Suarez ,

Thank you for reaching out to Microsoft Q & A !

Your trace shows that Entra authentication succeeds, but APIM rejects the subsequent developer-account registration with 400 ValidationError: User registration is not supported. This appears consistent with an APIM-side registration issue, although the cause for your instance is not yet confirmed.

Could you check API Management → Developer portal → Identities and confirm:

Whether the Username and password provider has been removed or disabled, leaving Microsoft Entra ID configured.
Your APIM SKU, and whether existing Entra ID users can still sign in.

This is a configuration check only—please leave your authentication and portal-access restrictions unchanged. Microsoft documents that the username/password provider can be removed when another provider such as Entra ID is configured, so I would not recommend re-enabling basic authentication as a fix. [learn.microsoft.com]

Reference: Configure developer portal authentication — Delete the username and password provider.

If registration remains blocked after confirming these details, an Azure API Management support request would allow instance-specific investigation. Include the APIM resource ID, subscription and tenant IDs, Canada Central region, exact failure timestamp in UTC, any request/correlation IDs, and the complete POST /users HTTP 400 response. Share these through the private support case, excluding tokens, cookies, and client secrets.

Please "Upvote the Answer" if this information helped you. This will help us and others in the community as well.