i thought that propogation might be an issue too, but it is still happening.
two machines in particular give that error message quite often.
i switched the network IP address of the machine (not the email server) and that fixed it for a day. now it's back again. it's weird as it's a pretty abrupt message most of the time, not a long timing out sort of thing. and it's somewhat itermintent, so it make sdiagnosing a bit of an issue.
i will try the IP address for the server in place of the 'mail.domain.com' and i'n also going to try using the allegiance email servers (the isp that provides the fractional T1).
another user has the same problem each day, but restarting fixes it. i dont really have too much issue with that, as it gets resolved on restart and seems to be fine for the day, althought it'd be great if it just worked, and she's not happy with the restart solution.
any other suggestions would be great. i'm beginning to think it's an isp (internet connection provider, not hosting) issue, but i don't know what the problem is.
thanks.