Sending to local user gives too many hops

Question

I have set up Mavericks server for mail. Works perfectly for incoming and outgoing mail to other domains but fails when trying to send mail to a local user. Here are my settings:
example.com is my primary domain, it provides DNS and Mail service
there are other domains being hosted (web) with example.com providing mail service for them.
Mail Server setting under "Provide Mails for...": Domain Name is example.com, Virtual domains: myotherdomain.com, example.com (included in list, is this correct?), and some more
DNS settings: each domain has a machine record for the domain name (e.g. example.com has an A record, myotherdomain.com has its own A record), each domain has an MX pointing to example.com. Domain example.com has an alias (CNAME) record mail.example.com pointing to example.com. This is the only place where the name mail.example.com appears in the whole server.
Last night I tried to reply to a mail I received from a user on myotherdomain.com. My receiving account is also on myotherdomain.com (myotherdomain.com is one of my domains with MX pointing to example.com). When I simply hit reply the mail server eventually reported back that the mail was not delivered due to too many hops.
Here are the headers from the mail I received. I simply hit reply and got the too many hops. WHY?
Return-Path: <[email protected]>
Delivered-To: [email protected]
Received: from localhost (localhost [127.0.0.1])
          by miniserver.example.com (Postfix) with ESMTP id 9EE9C4DA4D7
          for <[email protected]>; Wed,  5 Mar 2014 17:09:10 +0100 (CET)
X-Virus-Scanned: amavisd-new at example.com
Received: from miniserver.example.com ([127.0.0.1])
          by localhost (miniserver.example.com [127.0.0.1]) (amavisd-new, port 10024)
          with ESMTP id 3oDO8uq8aS6W for <[email protected]>;
          Wed,  5 Mar 2014 17:09:10 +0100 (CET)
Received: from miniserver.example.com (localhost [127.0.0.1])
          by miniserver.example.com (Postfix) with ESMTPA id 628CD4DA4BE
          for <[email protected]>; Wed,  5 Mar 2014 17:09:10 +0100 (CET)
MIME-Version: 1.0
Content-Type: multipart/alternative;
boundary="=_50c5075d15c85c7a43995d47cd97c851"
Date: Wed, 05 Mar 2014 17:09:10 +0100
From: anita <[email protected]>
To: [email protected]
Subject: Hello
Message-ID: <[email protected]>
X-Sender: [email protected]
User-Agent: Roundcube Webmail/RCMAIL_VERSION
Here is what the mail server reported back after trying to reply:
This is the mail system at host miniserver.example.com.
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
                  The mail system
<[email protected]>: host 127.0.0.1[127.0.0.1] said: 554 5.4.0 id=78365-11
   - Rejected by next-hop MTA on relaying, from MTA(smtp:[127.0.0.1]:10025):
   554 5.4.0 Error: too many hops (in reply to end of DATA command)
Reporting-MTA: dns; miniserver.example.com
X-Postfix-Queue-ID: 98CF04DB967
X-Postfix-Sender: rfc822; [email protected]
Arrival-Date: Wed,  5 Mar 2014 18:52:58 +0100 (CET)
Final-Recipient: rfc822; [email protected]
Original-Recipient: rfc822;[email protected]
Action: failed
Status: 5.4.0
Remote-MTA: dns; 127.0.0.1
Diagnostic-Code: smtp; 554 5.4.0 id=78365-11 - Rejected by next-hop MTA on
   relaying, from MTA(smtp:[127.0.0.1]:10025): 554 5.4.0 Error: too many hops
Thanks for your help

Answer 1

Invoke the following diagnostic by launching Terminal.app from Applications > Utilities and see if there are any network or DNS issues reported:
sudo changeip -checkhostname
Also post the internal and external DNS translations of the following:
dig +short miniserver.example.com
dig +short mail.example.com
dig +short MX myotherdomain.com
dig +short MX example.com
dig +short @8.8.8.8 miniserver.example.com
dig +short @8.8.8.8 mail.example.com
dig +short MX @8.8.8.8 myotherdomain.com
dig +short MX @8.8.8.8 example.com
I'd look for a bogus or missing MX record for myotherdomain.com, to start with.
FWIW, myotherdomain.com is a real and registered domain.    Probably not yours, I'm guessing.  The example.net and example.org domains are also available for obfuscation, in addition to the example.com domain.