Domain Email does not exist issue

Question

Hi,

I have a company domain, but when I try to login to the local account PC profile to change from local account to a M365 user account. I get the below error

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Moved from: Microsoft 365 and Office | Access | For business | Windows

Answer 1

Hello @Sean Hammond,

Thank you for posting your question in the Microsoft Q&A forum. 

The error “domain email does not exist” typically appears when the Microsoft 365 user account or domain you are trying to sign in with is not recognized in the tenant, or when there is a conflict with an existing object already using the same username/alias.  

To sign in with your business account, please go to your Windows PC and navigate to: 

Settings > Accounts > Access work or school 

From there, select “Connect” and sign in using your Microsoft 365 business account credentials. This will properly link the device to your work account. 

Note: Please understand that as a forum moderator, my primary goal is to provide helpful guidance and support through general troubleshooting steps. While I don’t have access to internal systems or test devices required to resolve backend/account issues, I truly appreciate your understanding of these limitations.  

I hope you find this information helpful. If you still encounter any issues after this step, please don’t hesitate to reach out to me. 

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Answer 2

The error typically occurs when the Microsoft 365 user name or email address being used on the PC either:

• Does not exist in the Microsoft 365 tenant, or
• Conflicts with an existing object (same UPN/email already used elsewhere in the tenant).

To resolve this, use the Microsoft 365 admin tools to verify and, if needed, correct the account:

1. In the Microsoft 365 admin portal, check that the user account you are trying to sign in with actually exists and is spelled exactly the same as what is entered on the PC (including domain, for example ******@contoso.com).
2. If the account exists but you receive a message like “A user with this name already exists. Use a different name.” when creating or editing it, follow these steps to locate conflicting objects:
   1. Connect to Exchange Online using remote PowerShell as described in Connect to Exchange Online Using Remote PowerShell.
   2. Run:

            get-mailbox | where {$_.EmailAddresses -match "user name"} | ft Name, RecipientType, EmailAddresses
      

      Replace "user name" with the part of the address you are trying to use.
   3. If another mailbox or object is already using that SMTP address/alias, change or remove the conflicting email address so the intended user can have the correct sign-in name.
3. After confirming the user’s UPN and primary SMTP address are correct and unique, return to the Windows PC and:
   • Go to Settings → Accounts → Access work or school (or Email & accounts) and add the work account using the verified Microsoft 365 username.
   • Then switch the local account to a work account or join the device to Azure AD using that same, verified UPN.

If the domain itself is already attached to a different Microsoft 365 tenant, the sign-in will also fail. In that case, the domain must first be removed from the other tenant before it can be used in the current one.

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References:

• "A user with this name already exists. Use a different name." error in the Microsoft 365 portal
• Error message when you try to verify a domain in Office 365