NotAcceptedDomainException when attempting to migrate Exchange Mailbox

Dieter Tontsch (GMail) 712 Reputation points
2022-04-06T11:42:48.597+00:00

I am trying to migrate a single mailbox from our on-prem Exchange 2016 to Exchange Online. I did this more then a year ago with success. But now it always fails with error: "Error: NotAcceptedDomainException: You can't use the domain because it's not an accepted domain for your organization.". This error sounds pretty straight forward, but fo rme it isn't.
The problem is that I have verified all Email domains of the user in charge and also the accepted domains from Exchange Online resp. Verified domains from Office Admin Portal.

These are the Email-Adresses for the user

X500:/o=ExchangeLabs/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=c308a8699b5846959d76912ead7af43f-Firstname Lastname
smtp:firstname.lastname@mobileX.intra
smtp:firstname.lastname@mobilexag.net
smtp:firstname.lastname@mobilexag.com
SMTP:firstname.lastname@mobilexag.de
smtp:firstname.lastname@mobileXAG.onmicrosoft.com
X500:/o=DOMAINNAME/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=8b8d193063a848cd9ab0169e8902b6ec-Firstname Lastname
smtp:firstname.lastname@mobileXAG.mail.onmicrosoft.com

And these are the accepted/verified domains.
Name Status Authentication


ext.mobilexag.de Verified Federated
mobilexag.online Verified Managed
mobilexag.de Verified Federated
mobileXAG.onmicrosoft.com Verified Managed
mobileXAG.mail.onmicrosoft.com Verified Managed
mobilexag.net Verified Managed
mobilexag.com Verified Managed

As you can see, all domains excepted mobilex.intra which is our internal DNS domain suffix (that one cannot be added to Office Online), are present. What is then the problem? I have to admin that mobilexag.com and mobilexag.net where not in place in Azure, but I added them afterwards, my migration batch still fails for several times. and I wonder, because my user I did migrate more then a year ago also definitely had an email address @mobilexag.com back then, and migration still went through successfully.

Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
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Microsoft Exchange Hybrid Management
Microsoft Exchange Hybrid Management
Microsoft Exchange: Microsoft messaging and collaboration software.Hybrid Management: Organizing, handling, directing or controlling hybrid deployments.
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Accepted answer
  1. Andy David - MVP 120.5K Reputation points MVP
    2022-04-06T11:50:54.247+00:00

    Can you remove that proxy address?
    smtp:firstname.lastname@mobileX.intra

    and then try again?


1 additional answer

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  1. GirtsG 0 Reputation points
    2023-02-23T07:41:16.0533333+00:00

    I'm looking for answer to same problem. Thing is that I can migrate user mailboxes having internal email address just fine. But to be able to migrate shared or resource mailbox internal email address must be removed. Still wondering why.

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