[imp] weird problem on imp with redhat 8

[Randall Badilla Castro]

Hi people:
I'm using horde+imp (recent versions, at least 1 version behind the 
latest) with apache1.3.7 and RedHat 8.
The imp send email fine to "non-localdomains" but within the same domain 
it fails with this error
"The original message was received at Wed, 4 Jun 2003 17:43:39 -0600
from localhost [127.0.0.1]

   ----- The following addresses had permanent fatal errors -----
<ramon_salas at hercules.mydomain.com>
    (reason: 553 5.3.5 system config error)

   ----- Transcript of session follows -----
553 5.3.5 ns.mydomain.com. config error: mail loops back to me (MX problem?)
554 5.3.5 Local configuration error .."
******
the sendmail.cf has
CWmydomain
Djmydomain.com
Fw/etc/mail/local-host-names --> this has the mailserver name and domain 
name and fqdn

*****
the dns has the mx to a fqdn with A record also (Not CNAME)

***
the imp/config/servers.php has been modified to remove 
hercules.mydomain.com but still I have errors sending mail to the users 
locals to mydomain.com....
When my users use another clients (eudora/ pegasus / incredimail) all 
works fine... just horde+imp give me this error !
Can anybody tell me whats wrong???
TIA

PD: I'm not using ldap or mysql for users preferences just plain files....

-- 

Randall Badilla Castro
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