Forum Discussion
Hybrid - traffic from on prem to EXO - 550 error, banned IP
Newly created Hybrid, a single mailbox migrated for testing. Mail flow from EXO to on prem works fine, but on prem to EXO traffic results in: VE1EUR02FT012.mail.protection.outlook.com #<VE1EUR02FT0...
Would be intersting, if you will get some more details about this issue. But I doubt, you will.
So it all started working yesterday afternoon, having changed nothing else on our side. I can only assume that the IP un-banning takes a lot longer than the 30 minutes suggested.
It will be interesting to see whether it is still working on Monday.