Sometimes it is necessary to clean out the mail queue on your server. Emails being stuck cause the complete mail flow to stop or to dramatically slow down. Customers will complain and the server performance goes down hill. Time to look at the mail queue a little closer.
1. Login to your dedicated server via ssh and switch to the root user.
2. At the command line prompt type: exim -qff
At the command line type: exim -qff -d9