Hybrid - traffic from on prem to EXO - 550 error, banned IP

Bronze Contributor
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 #<VE1EUR02FT012.mail.protection.outlook.com #5.7.606 smtp;550 5.7.606 Access denied, banned sending IP

The IP in question has never been used for email traffic before today.

Thoughts and suggestions please?
4 Replies



the error message is just "banned IP"?


Did you check, if the IP is black listed for any reason? http://mxtoolbox.com/blacklists.aspx (or any other service to check black listed IPs)?




Checked the IP for blacklisting already, it isn't on any of the usual suspects.

The error says just that, banned ip, yes.

We've requested the IP be removed, so will do some more testing today.
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.