Need help attaching domain to my email

Question

My domain is already attached to another Microsoft 365 tenant I don’t control. I own the domain and need it released so I can add it to this tenant

Answer 1

Hello @Elea Support Services

I want to provide the information to support you with your concern:

• If you still can reach out to the global admin of this tenant, you can refer to the article below to remove the domain from that tenant and attach it to the new one (a domain can only be associated with one tenant at a time). 
• If you no longer have access to the old tenant, you will need assistance from the Microsoft Engineering back-end team, who can check and help you remove it. However, you will need to prepare certain information beforehand to prove that you are the legitimate owner of the domain. 

Although I cannot directly assist you, I can provide you with detailed steps to ensure you can contact the correct team for proper support:

Please follow the detailed steps below.

(If you are not the global admin, please kindly ask your IT Admin to do it for you)

• Sign into the "Microsoft Admin Center"
• After clicking on "Help & Support" button like this image, you can type "I need agent support via phone or email". After that, you can click on "Contact support"
• Choose contact method: "Phone"
• Fill all the information in this contact support details, please describe your situation carefully so they will have enough information to help you.
• Finally, clicking on "Contact me"

After completing them, you will receive an email appointment for a meeting to review this issue professionally together.

*For your reference:
*Remove a domain from Microsoft 365 - Microsoft 365 admin | Microsoft Learn
Add a custom domain to Microsoft 365 - Microsoft 365 admin | Microsoft Learn

If you still need my assistance, please come back with screenshots or any additional details so I can review it again and see if there’s anything more I can help you with.  

Have a nice day!  

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Answer 2

The domain cannot be attached to a new Microsoft 365 tenant until it is removed from the existing tenant. Because the current tenant is not under this organization’s control, the only supported path is to work with Microsoft support so they can validate domain ownership and remove or reassign the domain.

Action steps:

1. Collect proof of ownership
   • Ensure access to the domain’s DNS (at the registrar) or web hosting so DNS records or a verification file can be added if Microsoft requests it.
   • Have registration details from the registrar ready (account name, purchase records, etc.).
2. Contact Microsoft 365 support as the domain owner
   • Sign in to the Microsoft 365 admin center with an admin account for the tenant where the domain should be used.
   • At the bottom right, select Help & Support.
   • In Support Assistant, describe the issue clearly, for example: the domain is already registered in an unknown tenant and needs to be released, and that ownership can be proven via DNS.
   • If the automated suggestions do not resolve the issue, choose Contact support and open a service request.
3. Work with Microsoft’s support/data protection team
   • Support may ask to add a TXT or MX record, or a verification file, to the domain to prove ownership (similar to the standard domain verification steps used when adding a domain).
   • After verification, Microsoft can remove the domain from the unknown tenant or otherwise free it so it can be added to the correct tenant.
4. Add the domain to the correct tenant once released
   • In the target tenant, go to Settings > Domains > + Add domain in the Microsoft 365 admin center.
   • Enter the domain and follow the wizard to verify ownership and add DNS records, either via Domain Connect (if the registrar supports it) or manually:
     • Verify ownership using TXT/MX record or website file.
     • Add the required DNS records for Exchange Online, Teams, and other services.
   • Complete the wizard until Domain setup is complete is shown.
5. Update user email addresses (if needed)
   • After the domain is successfully added, go to Users > Active users, edit each user’s username, and change it to use the new domain so email can be sent/received with that domain.

If there is no access to any admin account on the unknown tenant and the domain is still blocked, the support request is mandatory; forum moderators or self-service tools cannot remove a domain from another tenant.

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References:

• Add a custom domain to Microsoft 365
• Change your Microsoft 365 email address to use your custom domain
• Add your Google Workspace domain to Microsoft 365
• Domain is in another o365 as a tenant - Microsoft Q&A