qmail+squirelmail+vmailmgr problem

[cotty cotty info]

I recently installed teh qvcs package (squirelmail+vmailmgr+qmail) on a
redhat 7.3 box, but I have problems to sending email to some domains (for
instance xnet.ro) to which another mail-server on the same network (based
on debian/exim) has no problem in sending mail.

Can anyone help me ??