Exchange 2003. Only some users having mail delay.

Hey guys,

So here's what is going on... I am trying to look into why some users are having mail delay issues. I am running Exchange 2003.

In one example: I have a user from an outside organization who is sending to 5ppl within our company. For some reason, 2 of them get the message at the exact time that it enters the exchange queue, and 3 of them get it 15 minutes later.

I've gone through all of our logs to ensure that there wasn't any SPAM or greylisting issues, etc... I should also note that the mail is being forwarded over a mail connector to another Exchange server at another location. I used the message tracking features in Exchange as well, and after locating the e-mail that I am researching, it does not indicate any problems, but does show that it sent to 2 of the users' mailboxes on time, and the other 3 users 15mins later.

Has anyone else ever run into this? Any ideas?