I have two hosting accounts, personaldomain.com and companydomain.com. Both have User level cPanel. Whenever I try to send email from personaldomain.com to any email address on companydomain.com, I instantly receive a Mail Delivery System message saying:

Subject: **Mail delivery failed: returning message to sender**

A message that you send could not
be delivered to one or more of its
recipients. This is a permanent error.
The following address(es) failed:

  No Such User Here

This only happens from personaldomain.com to companydomain.com, and not the other way. I've tried each address, and looking at the headers, it doesn't seem to be leaving my mail server:

Received: from ns1.usm4.siteground.biz ([my-ip-address] helo=mymailserver1.usm4.siteground.biz)
         by se8.mailspamprotection.com with esmtps (TLSv1.2:DHE-RSA-AES256-SHA:256)
         (Exim 4.85)
         (envelope-from <myemail@personaldomain.com>)
         id 1aYcMc-0003NN-Qz
         for theiremail@companydomain.com; Wed, 24 Feb 2016 10:32:37 -0600
 Received: from localhost ([]:38882 helo=mymailserver.usm4.siteground.biz)
         by mymailserver1.usm4.siteground.biz with esmtpsa (TLSv1:DHE-RSA-AES256-SHA:256)
         (Exim 4.80.1)
         (envelope-from <james@duckduckloop.com>)
         id 1aYcMc-0007Zf-Lg
         for theiremail@companydomain.com; Wed, 24 Feb 2016 11:32:34 -0500
 Received: from an-ip-address ([an-ip-address]) by mysubserver.sgcpanel.com
  (Horde Framework) with HTTP; Wed, 24 Feb 2016 16:32:34 +0000
  Date: Wed, 24 Feb 2016 16:32:34 +0000
 [more content headers and filters]
 X-SpamExperts-Outgoing-Class: ham
 X-SpamExperts-Outgoing-Evidence: Combined (0.29)
 X-Recommended-Action: accept

I also noticed that the returned emails have a time of 4:32am when my server is 11:32am EST (sending from Webmail Horde) and my local time is 10:32am (sending from Outlook or iPhone). I don't know if that affects the authentication.

I'm able to send to companydomain.com from any other email address. I'm able to send to any other domain from personaldomain.com.

How can I figure out the source of this error, so I can fix it?

  • Thought I should add that I've whitelisted both domains between each other. – AceOS Feb 24 '16 at 17:31

A 550 error code means that your SMTP server isn't able to deliver the sent email to the user because recipient mailbox does not exist. According to me if your hosting account is running on shared environment rather than dedicated then please contact your hosting service provider and say them to check your e-mail functionality. Might be your email functionality have disabled by them for any bla bla reason.

  • Thing is, it works for every other domain I've tried. It's only from one specific domain to another specific domain. It is a virtual server, but I control all the MX records and spam settings, just don't know where to find the error log. – AceOS Feb 24 '16 at 20:13
  • Can you you please paste some exim_mainlog. so i can assist you better. – mAfiA Feb 25 '16 at 17:44
  • It turns out it wasn't anything to do with the email system. I started working on another server-side project, and my personal server could not reach my work server through HTTP request, so I started digging, and apparently it's a DNS issue of some kind. I have both hosting companies working on it. – AceOS Feb 26 '16 at 23:56
  • You mean CASE CLOSED :D – mAfiA Mar 1 '16 at 4:23

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.