I cannot link my domain because is linked in other tenant which I don't have access

Dear @Josep Pages,

I hope you’re having a good day.

Thank you for posting your question and for explaining the background in detail. I understand that you’re trying to add your custom domain to a new Microsoft Entra tenant, but the domain is already linked to another tenant that you no longer have access to. You’ve also tried the external admin takeover process, but it did not work, even though you can prove ownership of the domain.

The admin takeover process only works when the domain is associated with an unmanaged tenant (for example, a tenant created through self‑service sign‑up where the domain was never fully verified). If the domain was already verified in the past and is part of a managed tenant, the takeover process is blocked by design. In those cases, proving domain ownership via DNS is not sufficient to automatically remove or move the domain to another tenant.

Since you mentioned that a colleague likely linked and verified the domain several years ago, this strongly suggests that the domain is currently attached to a managed tenant. That would explain why the external admin takeover process does not succeed.

Unfortunately, there is no self‑service or portal‑based method to force‑remove a verified domain from another tenant when you don’t have admin access to that tenant. Forum moderators and the community also don’t have the ability to detach domains.

The only supported path forward in this situation is to contact Microsoft Support and request assistance with a domain recovery or tenant ownership verification. After validating your ownership of the domain and reviewing the status of the original tenant, Microsoft can determine whether the domain can be removed from the old tenant and made available for use in your new one.

Please try to find the related hotline number to call the frontline let them raise a ticket for you: Customer service phone numbers - Microsoft Support 

Depending on your country or region, when you call the support number, you may hear an introduction of about 30 seconds such as "you can visit the link...". You can ignore this introduction and wait until you are presented with the options. Then press "1" as a business email user, and again "1" for technical help 

I hope this information helps point you in the right direction. If you run into any issues while trying the steps, or if something still doesn’t feel quite right, please don’t hesitate to reach out again. I’ll do my best to support you however I can.  

Looking forward to hearing back from you with any updates or additional details. 

Warm regards, 

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