550 5.1.7 smtp authentication from one server

[robertjw]

I have a client using Outlook sending email through my cPanel server. We changed to a new hosting provider a few months ago and the new cPanel is setup to require smtp authentication.

The Outlook client uses IMAP and is setup to require smtp authentication and use port 587.

Everything has been working smoothly, but today he called and can't send email to one specific server. The message comes back with this message "550 #5.7.1 Your access to submit messages to this e-mail system has been rejected."

Here is the server log info.

2013-10-18 13:56:52 1VXFEC-0000a7-30 SMTP connection outbound 1382122612 1VXFEC-0000a7-30 domain.com [email protected]
2013-10-18 13:56:53 1VXFEC-0000a7-30 ** [email protected] R=dkim_lookuphost T=dkim_remote_smtp: SMTP error from remote mail server after RCPT TO:<[email protected]>: host c65
0-2.ispdomain.com.com [216.228.xxx.x]: 550 #5.7.1 Your access to submit messages to this e-mail system has been rejected.
2013-10-18 13:56:53 cwd=/var/spool/exim 7 args: /usr/sbin/exim -t -oem -oi -f <> -E1VXFEC-0000a7-30
2013-10-18 13:56:53 1VXFED-0000aH-Sl <= <> R=1VXFEC-0000a7-30 U=mailnull P=local S=4391 T="Mail delivery failed: returning message to sender" for [email protected]

My questions are:

1. Why is this happening on one email server (we tried multiple addresses)? I read about the pbl and everything there says the Outlook authentication settings should fix any problems there.

2. Is this coming from my server? Seems strange to me that the message is originating with my server when the problem is only with this one address.

3. Can I test and verify the smtp authentication is working? I've looked in /etc/relayhosts and it's empty. Could this be the problem?

Any help is appreciated!

Thanks!

 

[cPanelMichael]

Hello

The logs you provided indicate the message was rejected by the remote mail server. The remote mail server did not provide a specific reason why the message was blocked. I recommend contacting their mail administrator directly to see if a specific reason is available. Or, check to see if their IP address, or the server IP address used to send email is listed on any SPAM black lists. To note, you should not have to troubleshoot any issues with Outlook or SMTP authentication because you can send normally to other mail servers.

Thank you.

 

[robertjw]

OK, thanks. That's what I thought, but the administrator on the remote server said the message was coming from my server.

I agree about troubleshooting Outlook, but I need to be sure it's not my problem to keep my customer happy.

 

[cPanelMichael]

I would check to see if their personal IP address is on any SPAM black lists in the event that the mail server IP itself is not listed on any.

Thank you.