Forum Discussion
Exchange online users can't send or receive email in Hybrid configuration.
Hello, I'm testing a hybrid deployment with Exchange 2019 on prem. The hybrid setup seemed to go smoothly and I can migrate mailboxes between on-prem and online and back again. The problem I'm hav...
Have you configured centralised mail flow (all outgoing mail from Exchange Online routes via the on-prem Exchange servers)? Without having much detail, it looks like your on-prem network is blocking connections from Exchange Online to your on-prem Exchange server. Look at the connector in Exchange Online and make sure it validates fine. A message trace performed in Exchange Online will also show some more information which may shed some light on the issue
Thanks Dan.
Centralized mail transport is Not enabled, so email to the internet should route directly out of Exchange Online, yet I get the "Access denied, traffic not accepted from this IP" bounce back.
There are 2 connectors in Exchange online, Inbound (Your Org to O365) and Outbound (O365 to Your Org). The Outbound connector successfully validates and the on-prem mailbox receives the validation email. Inbound mail from the internet routes through the on-prem server and are delivered to the online mailbox, so the Inbound connector looks like it's working too.
- You've said you're only testing hybrid.....so it's possible the problem is outlined here https://learn.microsoft.com/en-us/exchange/troubleshoot/email-delivery/ndr/fix-error-code-5-7-700-through-5-7-750#57708-access-denied-traffic-not-accepted-from-this-ip