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I need backend cleanup for a stale proxy address blocking custom domain deletion

Mark Norwood 0 Reputation points
2026-05-27T04:05:11.3966667+00:00

Tenant/user state:

  • Tenant is now accessible and I have Global Administrator access.
  • User UPN is now my @.onmicrosoft.com address.
  • Licenses have been removed.
  • Custom domain **.com is no longer primary.
  • Domain deletion still reports 1 user reference.
  • Entra admin center shows the remaining user proxy address: @.com (my primary email address)

Self-service attempts:

  • Exchange Online PowerShell cannot find the recipient:

  - Get-EXORecipient @.onmicrosoft.com returns NotFound.

  • Microsoft Graph shows proxyAddresses as read-only.
  • Update-MgUser attempting to modify proxyAddresses fails with: Property 'proxyAddresses' is read-only and cannot be set.
  • Update-MgUser attempting to modify mail/otherMails also fails with: Authorization_RequestDenied / Insufficient privileges.

I am the sole owner and user within this tenant (which had been lifecycle locked because I discontinued use after initial setup years ago).

How can I remove the stale proxy address/domain reference from the backend? Can you please advise regarding the supported backend procedure to remove this cloud-only user reference so my domain can be deleted from the tenant?

Specific tenant and email address can be provided to MS Support upon request.

Microsoft Security | Microsoft Entra | Other
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  1. Taz 9,366 Reputation points MVP Volunteer Moderator
    2026-05-27T06:39:10.6966667+00:00

    Hi Mark,

    This is a known issue where a stale proxy address persists in the backend even after all self-service options are exhausted. Since Graph API returns proxyAddresses as read-only and Exchange Online can't find the recipient, the object is orphaned at the directory sync level.

    Open a support ticket with Microsoft — this requires a backend intervention that cannot be done through any admin portal or PowerShell cmdlet available to tenants.

    1. Go to Microsoft 365 Admin Center → Support → New service request
    2. Category: Entra ID (Azure AD) → Domain Management
    3. In the ticket, state:
      • You need a stale proxy address removed from a cloud-only user object
        • Get-EXORecipient returns NotFound (no mailbox exists)
          • Graph API shows proxyAddresses as read-only
            • The orphaned reference is blocking custom domain deletion
            1. Provide your tenant ID and the specific UPN/proxy address

    Microsoft backend support can directly remove the orphaned proxy address entry from the directory partition. This is a routine escalation for their Entra/Exchange backend team — usually resolved within 24-48 hours once the ticket reaches the right team.

    Note: If the admin center support option isn't available (due to the tenant's previous lifecycle lock), call Microsoft 365 support directly or use the Azure Portal → Help + Support path with your Global Admin credentials.

    Regards,

    Taz-Mvp

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