UPDATE NOV 1, 2022: Cross-tenant mailbox migration is now generally available! See Cross-tenant User Data Migration is Now Generally Available for details.
Historically, wh...
Updated Jan 07, 2025
Version 10.0
Blog Post
Cross-Tenant Mailbox Migration OAuth Errors: a lesson learned
TLDR: make certain you paste the correct Tenant GUID (SOURCE vs TARGET)
It turned out we had the wrong GUID in TWO places and this double error was confounding troubleshooting.
- First Error: wrong GUID set in the Organization Relationship
The output of (Get-AzureADTenantDetail).ObjectId on the TARGET should match the output of (Get-OrganizationRelationship).DomainNames on the SOURCE tenant.
If not, Set it on the SOURCE relationship side. (Please don't try to change it on your target AzAD side.)
- Second Error: wrong GUID used when calling VerifySetup.ps1 on the source side. This prevented the script from detecting the first error.
When you run the verify script on the SOURCE, erroneously using the SOURCE GUID instead of the TARGET GUID, it may tell you that all tests are Passed, even if the Organization Relationship is not correct.
I hope this helps somebody.
Big Thanks to Roman for bringing fresh eyes to the case and pointing out the problem.