Azure AD Application Proxy - "External Url entered is already in use for an application on another tenant" after tenant migration

PatrickV76 96 Reputation points
2021-03-08T16:25:25.137+00:00

I moved a custom domain from one tenant to another. I then deleted an enterprise application from the old tenant and re-created it on the new tenant. But when I try to change the "External Url" in the new tenant, I get an error message stating that "External Url entered is already in use for an application on another tenant." I checked the old tenant but the custom domain is gone. The enterprise application is gone. The app registration is gone. I even deleted the app in "Deleted applications (Preview)". What do I need to do more? Or is there a mandatory waiting period?

Microsoft Entra ID
Microsoft Entra ID
A Microsoft Entra identity service that provides identity management and access control capabilities. Replaces Azure Active Directory.
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  1. PatrickV76 96 Reputation points
    2021-03-10T22:03:49.663+00:00

    The following was my solution. A bit dirty but it works.

    New tenant

    • Removed enterprise applications
    • Deleted custom domain
      Old tenant
    • Added custom domain
    • Created enterprise application with custom domain
    • Changed custom domain to ****.onmicrosoft.com
    • Deleted the enterprise application
    • Removed the custom domain
      New tenant
    • Added the custom domain
    • Created the enterprise applications with the custom domain

    Succes!.

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  1. JamesTran-MSFT 36,376 Reputation points Microsoft Employee
    2021-03-10T20:53:58.99+00:00

    @PatrickV76
    Thank you for the detailed post and for your time and patience throughout this issue!

    I was able to find some similar issues on our end regarding the error message you received, and based off these issues, I'd recommend opening a support request. This way our engineering team can take a look at the backend to see if there are any old/orphaned apps that could be affecting your enterprise app migration.

    If you have any other questions or need help creating a support request, please let me know.
    Thank you for your time and patience throughout this issue.

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