Need help ASAP

Living in Europe my sysadmin is on break and I can't get to anyone else. I need to fix my mail server and I can't do it myself.

Right now according to dashboard from my Linode mail server is running, but not accessable from outside. I rebooted mail server to clear it, but it did not helped.

It happened a few month ago and sysadmin noted: "Antivisrus and antispam services were down on the server because of out of memory. Unfortunatelly I can't detect a reason why this happens. I have restarted stopped services and mail should work now."

This is time sensitive, anyone who can help? Not sure where else to turn. If this is the wrong forum or way to ask for help, then please direct me to the right way/.location.

Thank you advance.