Subdomain on B2C tenant wont verify

Question

Subdomain on B2C tenant wont verify

Fred Warren 0

We're setting up a standard login service using Entra External ID. We have a domain in a b2b tenant as well as a front door service running there with a subdomain verified against a cname successfully from our dns. We're trying to get the userflow working against this subdomain in the b2c tenant, however the subdomain won't verify in the b2c tenant using the TXT records we added in to the DNS. As such we can't get the userflow for sign on to work. We've been through a couple different LLM troubleshooting loops and just can't get this working. All that said this must be a pretty standard pattern and an easy solve from someone who's done this path before.

Rukmini 42,510 Reputation points Microsoft External Staff Moderator

2026-06-12T00:30:49.29+00:00

Hello @Fred Warren

Based on your description, it seems that you are unable to verify your custom domain in your Entra ID tenant, even after correctly adding the TXT records in your domain provider side.

This issue often occurs when the domain has already been verified in another Entra directory, as explained in the following document: Common verification issues

To resolve this, the recommended approach is to contact the Microsoft Data Protection team. You can reach them by calling Microsoft Customer Service using the phone numbers listed here: Customer service phone numbers - Microsoft Support.

If it doesn't work for you, please don’t worry—let us know, we are happy to assist you further!
Rukmini 42,510 Reputation points Microsoft External Staff Moderator

2026-06-12T17:04:20.8533333+00:00

Hello @Fred Warren Following up to see if you were able to create the support ticket, otherwise please let us know, we are happy to assist you further!