Global Admin Locked Out – "Account does not exist" after Primary UPN change

Question

Problem Summary:

I am the sole Global Administrator of my Microsoft 365 tenant. I changed my Primary User Principal Name (UPN) from the default [Moderator note: personal info removed].onmicrosoft.com to my custom domain [Moderator note: personal info removed]

Current Status:

Immediately after the change, I was logged out. Now, when I try to log back in, the system returns the error: "This account does not exist" for:

1. The new custom domain email address.
2. The original onmicrosoft.com admin address.

Troubleshooting already performed:

• Cleared browser cache and cookies.

• Tested login in Incognito/InPrivate mode (Edge and Chrome).

• Waited several hours for DNS and UPN propagation.

• Attempted to use the "Forgot Password" flow (System says user not found).

The "Catch-22" Issue:

I cannot open a support ticket via the Microsoft 365 Admin Center because I am the only administrator and I cannot authenticate. I am completely locked out of my business environment.

Request:

I need this case escalated to the Data Protection Team immediately. I am prepared to verify domain ownership via DNS TXT records to prove my identity and regain access to my tenant.

Answer 1

Hi @Adam Vigas,

Thank you for reaching out and for clearly outlining the issue. I understand how urgent and difficult this situation is - being the sole Global Administrator and suddenly locked out of your Microsoft 365 tenant, especially after a UPN change, is incredibly disruptive. When both the custom domain and the original onmicrosoft.com admin address return “This account does not exist,” it creates a full access-block that you cannot resolve through normal recovery paths.

Since you are the sole Global Administrator for the tenant, please follow the steps below to complete the account recovery process and regain access. 

Option 1: Contact Microsoft Data Protection Support by Phone (Primary Method)   

To regain access to your admin account as you can't access the Admin Portal, you can try reaching out to our Global Customer Service phone to raise a request for resetting your authentication method here: Customer service phone numbers - Microsoft Support. During the call, request to speak to an agent, and share with them every detail related to your query and also mention that you are the only admin lost access to your account. This should allow you to contact the appropriate team so you can solve this incident as soon as possible.  

   

Here are some tips and an example of a prompt to help you navigate the IVR more effectively:        

In some countries, it is an automated conversation like:  

IVR: What kind of problem are you concerned about?        

You: Authenticator.        

IVR: What kind of product do you use?        

You: Office 365 for business.        

IVR confirmation: education or company account?        

You: For companies        

IVR: Are you an administrator?        

You: Yes.        

IVR: Do you have another administrator in your organization?        

You: No.        

IVR: Do you need a... Service request?      

You: Yes. I need to create a ticket. Please send me direct to the Data Protection Team.   

 

 

Here are some details you can prepare for identity verification: 

• Domain ownership (DNS management access) 
• Billing/subscription details (payment methods, account history) 
• Tenant ID of the locked organization 
• Business registration documents 
• Authorized signatory documentation 

 

Option 2: Create a Temporary Account (Trial Tenant) to Submit a Support Ticket (Alternative Method)  

If you still cannot reach to a live agent, there is still a workaround, you might consider registering for a new tenant by signing up for a trial subscription via this link Microsoft 365 Business Plans and Pricing | Microsoft 365. This would allow you to create a new tenant following the prompts provided. Once set up, you can access the admin console of the new tenant and submit a support ticket requesting to speak with the Data Protection team on behalf of your previous tenant.        

 

Just to clarify, moderators do not have the ability to view or change user account information, so we cannot help with login issues, password resets, or modifying access rights. Even though we cannot access the internal tools required for account‑specific fixes, we are here to support you in every way we can within our scope. 

 

Please remember to cancel the trial subscription after your issue is resolved, as this will help you avoid any accidental billing. You may prefer the following resource for detailed instructions: Cancel your Microsoft business subscription in the Microsoft 365 admin center | Microsoft Learn  

    

I hope this helps you regain access to your account quickly. Please try the steps and let me know whether they resolve the issue. If the problem persists, we can work together to find a solution.  

As other users will also search for information in this community, your vote can significantly help those with similar inquiries quickly locate the most relevant resources. 

Thank you for your kindness and for contributing to the forum.   

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