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Accepted domains not provisioning after migration in Exchange Online

Pitman Donny 0 Reputation points
2025-10-22T12:49:26.2166667+00:00

After completing a migration to Exchange Online, I noticed that newly added accepted domains show as verified in Microsoft 365 but aren’t fully provisioned. Users can’t send or receive emails using the new domain, even though DNS and licensing appear correct.

I’ve confirmed that DNS records (MX, SPF) are properly configured, and the domains are verified in Azure AD. However, mail flow still only works under the original domain.

Is there a known issue or delay affecting accepted domain provisioning in Exchange Online?

Exchange | Exchange Server | Management
Exchange | Exchange Server | Management
The administration and maintenance of Microsoft Exchange Server to ensure secure, reliable, and efficient email and collaboration services across an organization.
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  1. Steven-N 11,240 Reputation points Microsoft External Staff Moderator
    2025-10-22T14:21:23.1266667+00:00

    Hi Pitman Donny

    Thank you for reaching out to Microsoft Q&A forum

    Based on your description, I understand that after migrating to Exchange Online, newly added accepted domains appear as verified in Microsoft 365 and DNS records are correct, but users cannot send or receive emails using those domains.

    From what I research, this behavior typically occurs due to provisioning delays or incomplete synchronization between Microsoft 365 and Exchange Online. Even when a domain is verified and DNS records (MX, SPF) are properly configured, Exchange Online must finish adding the domain as an accepted domain and update recipient proxy addresses. Microsoft documentation notes that these changes can take up to 24 hours to propagate.

    Therefore, in this case, if the issue persists after 24 hours, I recommend raising a support ticket through the Microsoft 365 Admin Center to receive further assistance directly from Microsoft.

    User's image

    In the meantime, you can try the following approaches to see if they help resolve the issue:

    1. Confirm the domain appears in the Exchange Admin Center under Mail flow > Accepted domains and is set to Authoritative.
    2. Check that affected mailboxes have the new SMTP address in their proxyAddresses attribute and that synchronization has completed if you use hybrid.
    3. Validate DNS records against the values shown in the Exchange Admin Center (avoid legacy MX assumptions).

    Hope my answer will help you, for any further concern, kindly let me know in the comment section

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