NotAcceptedDomainException when attempting to migrate Exchange Mailbox

Dieter Tontsch (GMail) 897 Reputation points

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
X500:/o=DOMAINNAME/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=8b8d193063a848cd9ab0169e8902b6ec-Firstname Lastname

And these are the accepted/verified domains.
Name Status Authentication Verified Federated Verified Managed Verified Federated Verified Managed Verified Managed Verified Managed 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 and 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 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.
4,306 questions
Microsoft Exchange Hybrid Management
Microsoft Exchange Hybrid Management
Microsoft Exchange: Microsoft messaging and collaboration software.Hybrid Management: Organizing, handling, directing or controlling hybrid deployments.
1,951 questions
0 comments No comments
{count} votes

Accepted answer
  1. Andy David - MVP 143.6K Reputation points MVP

    Can you remove that proxy address?

    and then try again?

1 additional answer

Sort by: Most helpful
  1. GirtsG 0 Reputation points

    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.

    0 comments No comments