Incoming Email from Office 365 Distribution Group

tomdchi

Well-Known Member
Feb 24, 2008
140
3
68
Atlanta, GA
cPanel Access Level
DataCenter Provider
One of my customers is having an issue with email sent from a MS Office distribution group. After a couple of days they will get a email from MS saying that the emails failed to send.
The email says:

Your message wasn't delivered because, despite repeated attempts to contact it, the recipient's email system didn't respond.


Contact the recipient by some other means (by phone, for example) and ask them to tell their email admin that their email system isn't accepting connection requests from your email system. It's likely that the recipient's email admin is the only one who can fix this problem.


For more information, see Status code 4.4.7.


At the bottom of the email it displays this for every email that did not get sent:

Code:
12/4/2015 6:24:25 PM - Server at DM3PR1001MB1183.namprd10.prod.outlook.com returned '550 4.4.7 QUEUE.Expired; message expired'
12/4/2015 6:03:38 PM - Server at mail.ourserver.com (our IP) returned '450 4.4.318 Connection was closed abruptly'
I have looked through the exim log and found entries like this many times:

Code:
2015-12-04 13:08:59 SSL_write: (from mail-bn1bon0064.outbound.protection.outlook.com (na01-bn1-obe.outbound.protection.outlook.com) [157.56.111.64]:1390) syscall: Connection reset by peer
2015-12-04 13:08:59 SSL_write error 5
2015-12-04 13:08:59 SSL_write: (from mail-bn1bon0064.outbound.protection.outlook.com (na01-bn1-obe.outbound.protection.outlook.com) [157.56.111.64]:1390) syscall: Broken pipe
2015-12-04 13:08:59 SSL_write error 5
2015-12-04 13:08:59 SSL_write: (from mail-bn1bon0064.outbound.protection.outlook.com (na01-bn1-obe.outbound.protection.outlook.com) [157.56.111.64]:1390) syscall: Broken pipe
2015-12-04 13:08:59 SSL_write error 5
2015-12-04 13:08:59 SSL_write: (from mail-bn1bon0064.outbound.protection.outlook.com (na01-bn1-obe.outbound.protection.outlook.com) [157.56.111.64]:1390) syscall: Broken pipe
2015-12-04 13:08:59 SSL_write error 5
2015-12-04 13:08:59 SSL_write: (from mail-bn1bon0064.outbound.protection.outlook.com (na01-bn1-obe.outbound.protection.outlook.com) [157.56.111.64]:1390) syscall: Broken pipe
2015-12-04 13:08:59 SSL_write error 5
2015-12-04 13:08:59 unexpected disconnection while reading SMTP command from mail-bn1bon0064.outbound.protection.outlook.com (na01-bn1-obe.outbound.protection.outlook.com) [157.56.111.64]:1390
Anyone have any idea what the problem is or how to fix?
 
Last edited by a moderator:

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,904
2,220
463
Hello :)

This issue likely stems from the following option under the "ACL Options" tab in "WHM Home » Service Configuration » Exim Configuration Manager":

"Introduce a delay into the SMTP transaction for unknown hosts and messages detected as spam"

Per it's description:

The SMTP receiver will wait a few additional seconds for a connection when it detects spam messages in order to reduce inbound spam. The system excludes the following remote hosts from the delay: Neighbor IP addresses in the same netblock, Loopback addresses, Trusted Mail Hosts, Relay Hosts, Backup MX Hosts, Skip SMTP Checks Host, Sender Verify Bypass Hosts, and Greylist Trusted Hosts.


Does the issue persist if you temporarily disable this option, or add the Outlook IP addresses to the trusted mail hosts list?

Thank you.
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,904
2,220
463
I am happy to see the issue is now resolved. Thank you for updating us with the outcome.