MY SIP BLOCK SMTP Relay access denied -- 2 - 18/10/2017 17:43 EDT

I have my own epost server hosted on linux Debian with postfix and Dovcot My epost clients is Microsoft outlook 2015 I work a lot with customers or elsewhere. I experience up that email my not work because SIP / network admin has sprret port 25 (SNMP) to that I must use their SMTP server to send mail. I've tried to open my server with 2 ports. 25 and 9800 it did not solve the problem. I'm tired of having to change smtp server and ports to like that all tidne Anybody know a fix ?? or must I go over to webmail or Exhange server? for these error messages 'H****************' den 08.07.2016 21.26 Serverfeil: 554 5.7.1 <he****AT**,no>: Relay access denied 'E***************' den 13.07.2016 08.48 Serverfeil: 553 5.3.0 <er**AT*********',no>... We do not relay from [login to view URL]