I have an Exchange server whose MTA queue will backup about every 7 – 10 days. It is Exchange 5.5 SP4 on WinNT4 SP6a. The connector is an x.400 over a 56k frame relay to a bridgehead that is the same configuration. The bridgehead and the remote server get event IDs 289 (a connection with the remote exchange server could not be opened) and IDs 1293/1290 (a remote/local initiated association to the other server was refused with failure reason prider 0 and the reason was 0). This will go on for nearly the whole day that it happens, and will eventually start working again towards the end of the day. I have already ruled out network connectivity and bandwidth issues, and I have modified the MTA overrides according to MS TechNet with no success. I added a backup x.400 connector with a higher cost to another server, and now when it happens the queues will get stuck and swap between the two connectors. This is getting very frustrating. Any suggestions?