This issue started yesterday out of the blue. I'm running Server 2003 Standard SP1 with Exchange Version 6.5 SP2.
My messages pending submission que continues to grow mostly with spam. I currently have around 1000 items waiting. They are processed, but it is very slow. I cannot find where any updates may have been applied on this machine to change anything. It is running GFI 11.0, but I have it disabbled at the moment with no luck. It is also running Symantec Mail Security for Exchange, which I also tried disabling temporarily.
I turned the NDRs off, and have restarted the machine and the SMTP service a couple of times.
Forgive me if I have not provided enough information. I will be happy to supply more if it will help.
Any thoughts or suggestions are greatly appreciated.