I have an Exchange environment with 3 Exchange servers, 1 FE and 2 BE. Server 2003 Domain. I also have 1 SPAM filter that is also our incoming SMTP before any mail hits the Exchange boxes. We also suscribe to Message One email service, so that if our exchange environment goes down they will hold our mail for us and give us temp accounts that let us continue to use email. All Exchange boxes are Exchange version 6.5 Build 7638.2 SP2.
I have been seeing this issue happening more and more where my Exchange queue's are betting stuck on 5 or 10 messages. Sometimes I can clear the queue by forcing the connection, but other times the connection just won't connect, and I have to delete the messages from the queue and then force the connection for it to work. I seem to see the same user stuck in the queue a lot, not every time, but 75% of the time. She also happens to have the largest mailbox in the company, 15 GB's. The message sizes getting stuck are very small, no large attachments.
Also, sometimes it is the connection between one of the BE servers and the SMTP server, and other times it is the connection between one of the BE servers and the Message One service we suscribe to.
I can't see a pattern as to why this is happening, and I have looked in the event logs and don't see anything wrong. I don't have enough experience with Queue's to know how to troubleshoot this issue. Please help.