Email Hosting: cPanel (Exim) email loop – Too many “Received” headers – suspected mail loop

Email Hosting Issue: email looping on cPanel (Exim)

When your server’s email flow stops, it is like the lifeblood of a company that stops. As soon as an email issue appears we have to jump on them immediately and get to the core of the problem. Smart trouble-shooting is key. At this point, we have to look under the hood of cPanel. cPanel (WHM) is an email hosting and website hosting automation control panel.

Every now and then, you get a cryptic bounce message that drives you to dig deeper. In this case, we first saw “potential email loop” in the bounce message. However, that was not enough. We had to then look at the email logs on cPanel. The place to look was “Track delivery.” Meanwhile, the customer’s email is bouncing, and the pressure is mounting. In the end, we were able to fix the issue quickly.

Problem: email loop detected on email hosting server

You see the following symptom. You send mail to a user on cPanel, and the following error is displayed in the “Track Delivery” section of the users cPanel account:
Too many "Received" headers - suspected mail loop

Solution: fix MX settings of the email hosting control panel (WHM cPanel)

  • Go to the MX record section of cPanel.
  • Reset the delivery method to local.
  • If the method is already set to local, make sure you change it to “backup”, save, and then back to local.

What else can cause a mail loop? Make sure that you do not have a conflict in domain forwarder or email forwarder.

Background

cPanel uses Exim. On Exim, the destination domain is in /etc/localdomains. If the email is stored on a remote server, list the domain in /etc/remotedomains. The steps to take in the solution section act on the MX record editor of cPanel. These steps force cPanel to properly populate these files.

If you have similar issues and have a hard time figuring out the solution, let us know. We are happy to help with any email system, cPanel, Plesk, Domino, or Exchange. Contact us at support at www.newpush.com, or through the contact us page.

Interested? Click here to contact us for a free consultation →