Domain already added to another Microsoft 365 tenant - no access to old tenant

TI Bolamel 0 Reputation points
2026-09-20T18:09:53.9233333+00:00

We are trying to add our domain bolamel.com.br to our current Microsoft 365 tenant, but we get this message: "We confirmed that you own bolamel.com.br, but we cannot add it to your account because the domain has already been added to another Microsoft 365 organization: uhv3czr8541nvi.onmicrosoft.com. Log in to the admin center as an administrator for that organization, and remove the domain. Try resetting the administration password if you are unable to log in."

We do not have any access to that old tenant (uhv3czr8541nvi.onmicrosoft.com). No one in our company knows the login credentials, and we don't know which employee or partner originally created it, so there is no recovery email or phone number we can use to reset the password.

Our current Microsoft 365 subscription is managed through a CSP partner, but they have confirmed the old tenant was not purchased through them and they have no visibility or access to it either.

Could you please help release/remove our domain from that old tenant so we can add it to our current one? We can provide proof of domain ownership (WHOIS registration showing our company as the registrant) if needed.

Thank you.

Microsoft 365 and Office | Subscription, account, billing | For business | Other
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  1. Ivory 1,825 Reputation points Independent Advisor
    2026-09-20T19:48:17.5433333+00:00

    Hi TI,

    In this situation, the domain cannot be released until ownership has been successfully verified. The best course of action is to work directly with the Microsoft Data Protection Team, who are responsible for handling tenant recovery and ownership validation requests. Once they have reviewed your case and confirmed your ownership of the domain, they can facilitate the release of the domain from the old tenant, allowing it to be added to your new Microsoft 365 tenant. 

    To move toward a resolution, please open a support request from your new Microsoft 365 Business tenant: 

    • Sign in to the Microsoft 365 Admin Center using your admin account  
    • Select Help & Support (bottom-right corner)  
    • Enter a request such as “ I own and control the DNS for my domain, but it is currently attached to an old Microsoft 365 tenant that I can no longer access. I need assistance from the Microsoft Data Protection Team to verify ownership and release the domain so it can be added to my new Microsoft 365 Business tenant. The verification code is not being delivered to my business email or alternate email.”  
    • Choose Contact support and select your preferred contact method (chat or phone). 

    If you're unable to access the Microsoft 365 Admin Center, I recommend contacting Microsoft Support directly. You can reach them by phone using the contact numbers listed here: Customer service phone numbers - Microsoft Support  and choose Work account.    

    I hope this provides enough clarity and helps you stay inform with your current situation.

    If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.  

    If the answer is helpful, please click 'Yes' and kindly upvote it.

    Note: Please follow the steps in the forum documentation to enable e-mail notifications if you want to receive the related email notification for this thread. 

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  2. AI answer

    2026-09-20T18:10:11.76+00:00

    This cannot be released manually from the current tenant or by the CSP partner if the domain is still attached to an inaccessible old tenant.

    Use this decision path:

    1. Check whether the domain is actually stuck in the current Entra directory as Unverified.
      • Go to portal.azure.com → Microsoft Entra ID → Custom domain names.
      • If bolamel.com.br appears there with status Unverified, open it and select Verify.
      • Then return to admin.microsoft.com → Settings → Domains and continue setup.
    2. If the error still says the domain is already added to another Microsoft 365 organization (uhv3czr8541nvi.onmicrosoft.com), the domain is attached to a different tenant.
      • If that other tenant is an unmanaged account created by self-service signup, perform an internal admin takeover first.
      • In the takeover flow, verify domain ownership by adding the TXT record shown in the wizard. After becoming admin, remove the domain from that account and then add it to the current managed tenant.
    3. If there is no access to the old tenant and takeover is not possible, this requires Microsoft support.
      • Similar Microsoft Q&A cases for domains verified in a different directory were resolved by opening a support ticket so the Data Protection/support team could help restore access to the old tenant and resolve the domain association.
      • In Microsoft 365 admin center: Help & Support → enter the issue → Contact support.
    4. Before removing the domain from any tenant, confirm these blockers are cleared in that tenant:
      • The domain is not the default domain.
      • No users, shared mailboxes, resource mailboxes, or contacts use it.
      • No Microsoft 365 groups, distribution lists, or Teams use it.
      • No admin accounts use it for sign-in.

    Also note:

    • .onmicrosoft.com domains cannot be removed.
    • When a custom domain is removed, user accounts revert to the default .onmicrosoft.com address as the primary SMTP/UPN.
    AI-generated content may be incorrect. Read our transparency notes for more information.

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