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Exchange Hybrid Configuration HCW8001 Unable to determine the Tenant Routing Domain
I'm stuck on this error in HCW. Here's some background:
Added public domain to 365 domains and made it an 'accepted' domain in Exchange Online. The onmicrosoft domain is also an 'accepted' domain. Ran IDFix to prep accounts for Cloud Sync by fixing blanks and changing UPNs to use public domain. Installed/configured Entra Cloud Sync on two domain controllers without error and they show the domain is healthy. Ran HCW on Exchange 2016 server and got the error, "HCW8001 Unable to determine the Tenant Routing Domain".
The error has a link to this article: https://learn.microsoft.com/en-us/troubleshoot/exchange/hybrid-configuration-wizard-errors/unable-to-determine-the-routing-domain-for-the-cloud-org
Unfortunately, none of the commands in the article are recognized.
Can anyone help me get past this error?
Thank you in advance!
VasilMichev, thank you for your reply! I just found the solution. By default, Microsoft sets up a domain for customers, like company.onmicrosoft.com, which is automatically added to Exchange's Accepted Domains. In order for HCW to complete, it also needs a record with "mail" in it, like company.mail.onmicrosoft.com, added to Accepted Domains. Although both domains can be easily added to on-premises Exchange, only Microsoft support can add them to Exchange Online's Accepted Domains. I opened a support ticket, they added the domain, and HCW completed successfully.
FWIW: I think either the Entra Cloud Sync or the HCW is supposed to automatically add the "mail" domain because, in my test environment, it was automatically created. I suspect this is an intermittent bug that only affects some users, which would explain why the solution was hard to find.
5 Replies
VasilMichev, thank you for your reply! I just found the solution. By default, Microsoft sets up a domain for customers, like company.onmicrosoft.com, which is automatically added to Exchange's Accepted Domains. In order for HCW to complete, it also needs a record with "mail" in it, like company.mail.onmicrosoft.com, added to Accepted Domains. Although both domains can be easily added to on-premises Exchange, only Microsoft support can add them to Exchange Online's Accepted Domains. I opened a support ticket, they added the domain, and HCW completed successfully.
FWIW: I think either the Entra Cloud Sync or the HCW is supposed to automatically add the "mail" domain because, in my test environment, it was automatically created. I suspect this is an intermittent bug that only affects some users, which would explain why the solution was hard to find.
Yes, enabling dirsync should provision said domain, which is what the article you cited above is all about. Support can also fix it, so there you go :)
I have the same issue!
Open a support ticket in the Exchange Admin center. Tell them the domain is missing and ask them to "run diagnostics on their provisioning service". Tobi at Microsoft told me it gets hung up sometimes and does provision everything it should, like this domain name.
The cmdlets listed in the article are from the Entra module, it also tells you how to install it (first cmdlet). Alternatively, you can use the Graph API/SDK cmdlets to the same effect:
Update-MgOrganization -OrganizationId xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx -OnPremisesSyncEnabled:$true
