May 10 2018
04:28 PM
- last edited on
Feb 06 2023
03:18 AM
by
TechCommunityAP
May 10 2018
04:28 PM
- last edited on
Feb 06 2023
03:18 AM
by
TechCommunityAP
Created a Group in O365 and also a Distribution Group in O365. We have a Hybrid environment.
Cannot Email from External Email Address
This is the Error
This is the Email Security Gateway at host webmail.domain.com.
I'm sorry to inform you that the message below could not be delivered.
When delivery was attempted, the following error was returned.
<Test0365Group@domain.com>: host IP ADDRESS said: 554 5.4.6 Hop
count exceeded - possible mail loop (in reply to end of DATA command)
Final-Recipient: rfc822; Test0365Group@domain.com
Original-Recipient: rfc822;Test0365Group@domain,com
Action: failed
Status: 5.4.6
Remote-MTA: dns; IP Address
Diagnostic-Code: smtp; 554 5.4.6 Hop count exceeded - possible mail loop
May 10 2018 11:28 PM
As the NDR message suggests, you probably have some incorrect setup with your mail flow, causing a loop. As you haven't provided any details with respect to where the MX record point at, how connectors are configured and so on, we can only advise you to check your configuration. You can always open a support case to get this properly investigated.
May 11 2018 10:01 AM
I just sent a Private Message to Michev
We have a Barracuda Device and mx records points there and Barracuda will accept emails from both.
Only O365 Groups and DG has issue. Cannot recieve emails from pn-prem users and external users.
O365 users can sent emails
Mar 28 2019 02:56 AM
@Biju DanielsHi there, Did you find a resolution?
I am in the same boat. My mail flow is fine for On-Prem user to 365 users/shared mailboxes but I get an NDR for mail loop when an on-prem users sends an email to a 365 DL or Group.