After rebooting our Linux server, we cannot access our email. We are running Postfix IMAP email and port 143 does not seem to be available. I am new to the Linux world and am sure this is a very easy fix, but cannot find the answer. Can someone help???

Stopping and restarting postfix does not help. When trying to check email from Outlook, the message is that the server is now in offline mode.

This is the first time I have rebooted the Linux server that was installed and set up by someone else who is not currently available. Is there another command I need to run???

Thanks in advance for your help.

Postfix is an MTA (Mail Transfer Authority), it isn't what is providing you IMAP access. You need to figure out what IMAP server your running (probably courier-imap) and run the startup script for that as well.

It looks like I may be running dovecot, any idea on how or where to find the startup script, or to verify which IMAP server I am running.

According to the documentation all you have to do to run Dovecot is run the dovecot executable. The best way to find out is really to ask whomever set it up. Problem is theoretically there could be ten different imap servers installed on your machine, but only he would know which one he configured for you.