How to troubleshoot Diagnostic-Code: smtp; 554 5.4.6 Hop count exceeded – possible mail loop?
When someone sends an e-mail to our customers; they may receive the following bounce back and the sender in such a case might contact our customer with the following bounce back.
Reporting-MTA: dns; sfw1.apps4rent.com
X-Postfix-Sender: rfc822; email@example.com
Arrival-Date: Thu, 11 Feb 2010 04:51:26 -0500 (EST)
Final-Recipient: rfc822; firstname.lastname@example.org
Remote-MTA: dns; 192.168.168.241
Diagnostic-Code: smtp; 554 5.4.6 Hop count exceeded – possible mail loop
The sender gets this bounce back due to a mail loop. This is generally caused if our customer (email@example.com) has added his e-mail address (firstname.lastname@example.org) and more than two location in the control panel. For example: Our customer has added email@example.com as an e-mail address; is also a member of the distribution group called firstname.lastname@example.org and he has setup a forwarder for his email address email@example.com to firstname.lastname@example.org. In such a case; when the system receives an e-mail for email@example.com; it forwards a mail to firstname.lastname@example.org. Now as email@example.com is also a member of firstname.lastname@example.org; this forms a never ending loop.
Another example is that you have an e-mail address email@example.com and at the same time you have created a contact which has the same e-mail address which has e-mail address as firstname.lastname@example.org.
Please ensure that your e-mail address email@example.com is not added in such a fashion to a distribution group. Also, please ensure that your e-mail address is not created as contact also. You would not need to create a contact for your e-mail; as you have a mailbox you will be listed in GAL to your other users.
Note: Not all cases have been discussed here. These are some examples. However, if people are reporting to you that they are getting such a bounce back when they send an e-mail to you; then you need to check your account and see if your e-mail address firstname.lastname@example.org has been added twice in the system.
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