It seems you may have a corrupt queue. A sign that a queue is corrupt is if the oldest message exceeds the standard queue time of 72 hours (3 days). You can see this in "Monitor > System Status".
Do you know if there was a power failure in your network that may have caused the machine to be improperly rebooted? That is also another common cause of a queue to be corrupted.
The above are signs that the queue is corrupt. The good thing is that for the most part it's recoverable. You should contact IronPort Customer Support and they will log into your appliance via a secure ssh tunnel and verify this. They can also repair the queue, with your permission of course.
Good luck!
My C150 is getting this message and I cannot find anything on it or figure out how to fix it. Any ideas? Thanks!
