admin/people/profileCardProperties endpoint returning 500 UnknownError - Custom profile card properties not displaying

Describe the bug
Subject: admin/people/profileCardProperties endpoint returning 500 UnknownError - Custom profile card properties not displaying

Hello,

We are experiencing an issue with the Microsoft Graph People Settings API for one of our managed clients (tenant: VEIRenergy.onmicrosoft.com). The admin/people/profileCardProperties endpoint is returning a 500 Internal Server Error with an UnknownError code for all methods including GET, POST, and DELETE. As a result, custom profile card properties (Pronouns, Birthday, Hire Date) that were previously configured and working are no longer displaying on user profile cards in Outlook Web and Microsoft Teams.

The underlying user data is confirmed intact — extension attributes on individual user objects are still populated correctly via the /users endpoint. The issue appears to be isolated to the profileCardProperties admin endpoint.

Steps to reproduce:

1. Sign into Graph Explorer as a Global Admin for tenant VEIRenergy.onmicrosoft.com
2. Run GET https://graph.microsoft.com/v1.0/admin/people/profileCardProperties
3. Response returns 500 Internal Server Error with empty message

Request IDs for investigation:

• 72b433ea-fb97-4406-809d-6be46121d00a (June 8, 2026 ~15:02 UTC)
• 20cb7a4b-b33d-4349-ba3a-602aab7228fb (June 8, 2026 ~15:08 UTC)

Expected behavior: GET should return the list of registered custom profile card properties.
Actual behavior: 500 UnknownError with empty message body.

Please investigate and advise. Let us know if any additional information or tenant details are needed.

Thank you,
Amy Boudreau
1Point Networks
aboudreau@1point.net

Additional context
Add any other context about the problem here.

Start by reproducing GET https://graph.microsoft.com/v1.0/admin/people/profileCardProperties in Graph Explorer with the provided request IDs and compare its behavior with POST and DELETE. The issue is complete when the endpoint returns the registered custom profile card properties and they display again in Outlook Web and Microsoft Teams.