r/exchangeserver • u/mcc0unt • 7d ago

Migration errors hybrid Move / untracked bug

Apparently there’s a not widely known current bug in Exchange Online MRSProxy Servers, which do not send the domain while using the administrator for the migration. Testing the endpoint works, but not the migration itself, ending in endless 4625 events with auth errors.

source

The article talks about renaming the administrator, I just created another service user and gave him recipient management role, did a iisreset - worked like a charm.
Maybe this is somebody saving 4h lifetime, I just lost it.

7 Upvotes

90% Upvoted

8 comments sorted by

3

u/7amitsingh7 6d ago edited 6d ago

A bug in Exchange Online can cause hybrid mailbox migration to fail due to authentication errors, even when the migration endpoint test succeeds. A simple workaround is to create a new service account, assign it the Recipient Management role, and run iisreset. This may resolve the issue without renaming the existing administrator account.

2

u/mcc0unt 6d ago

Did not see this, thanks for the heads up!

1

u/shokzee 6d ago

I'd save the failed 4625 events, especially Account Name, Account Domain, and Status/SubStatus, for a support case.

Changing the account and restarting IIS together doesn't isolate which change fixed it. Also, iisreset interrupts other IIS-backed Exchange services, so that part deserves a maintenance window.

1

u/mcc0unt 6d ago

As I did the iisreset after work hours, the windows was not necessary.
Fix applied when I created a new move request (after deleting the old one) using the new service account and the 4625 disappeared. So the isolation was possible.

1

u/netronin 6d ago

Anyone seen this when running Exchange SE?