Exchange 2016 Hybrid

[Adam CookRedding]

Hi we have a hybrid setup however when i move a mailbox to office 365 they can send email but cant receive any email at all, if i move the same mailbox back to on premise it can send and receive email fine. I am convinced that there is a problem with the receive connector on 365 or the send connector to office 365 because our spam filtering shows the email going through fine and its out exchange bouncing back with the email below.

Your message:
From: (email address from)
Subject: test

Could not be delivered because of

Server refused mail at END OF DATA - 554 5.4.12 SMTP; Hop count exceeded - possible mail loop detected on message id <8d9e9b9560b14ca28c07a698e4296865@domain.com>

The following recipients were affected:
365.Migration@domain.com




Additional Information
======================
Original Sender: <email address fromm>
Sender-MTA: <127.0.0.1>
Remote-MTA: <public ip address>
Reporting-MTA: <spam filter>
MessageName: <B5e53bb800002.000000000001.0003.mml>
Last-Attempt-Date: <12:03:13 Mon, 24 February 2020>


I couldn't find a guide to setup the 365 connectors at all, and speaking to 365 support, they just tell me its an issue with the on-premise server and i have to pay for support. Can anyone give a hand how to do this.