Hello every body I had problem with post master mail account in otrs 2.3.3 recently and I can't receive my email in otrs queue(however I can send email with otrs). now I install otrs 2.3.4 win 32, I install it in my windows 2003 server. I use kerio mail server and create a domain (mydomain) and 2 users (admin,hassani) I run my otrs system as admin and click on admin button and then sysconfig in core window I set "AdminEmail" element with "admin@mydomain" but when I submit the page it doesn't change my "AdminEmail" with my email address and it has it's default address. And in my log file I don't receive any messages. and so when I want to add new user and set user EmailAddress element with hassani@mydomain.com I receive 2 errors in my log file: [Kernel::System::CheckItem::CheckEmail][161] DNS problem: Unknown error [Kernel::System::User::UserAdd][263] Email address (hassani@mydomain.com) not valid (invalid hassani@mydomain.com (DNS problem: Unknown error)! )! but when in sysconfig core window I set "CheckMXRecord" element with "No" then I can add my user with hassani@mydomain.com and don't receive any error. and other question: what is "FQDN","CheckMXRecord","CheckMXRecord::Nameserver" elements in core window and if I use mail server on my local system, with what value I must set these elements? Thanks.