A cloud-based identity and access management service for securing user authentication and resource access
Hello ohpreis,
Thank you for your time over the call.
As discussed, the custom domain you're trying to verify is already in use within your main directory. Due to current limitations in Microsoft Entra ID, a custom domain can only be verified in one directory at a time. If you attempt to verify the same domain in another directory, the verification will fail—even if the correct TXT and MX records are configured at the DNS level. You can refer to the documentation below for more details:
Regarding the MPN ID verification for your application, it cannot be completed unless the custom domain is verified in the same directory where the application is registered. You have two options:
- Verify the custom domain in the current directory where the application is hosted (which would require un-verifying it from the main directory first), or
- Add a new custom domain to the current directory and obtain an MPN ID associated with that new domain.
This will allow you to link the MPN ID to your application successfully.