We're running a 2008 SBS server providing email and file services to 10 users. This server has been running fine for 6 months but one of the users has started getting bouncebacks when sending mail to a client with an aol.com email address (the address is valid). The bounceback says:
#550 4.4.7 QUEUE.Expired; message expired ##
I've run the Exchange Tools and it seems there are a few of these bouncebacks to different domains over the last few months but this is the first time I've been told about them. I'm a bit of a novice to Exchange 2007 and DNS but I've heard that I may not have reverse dns setup. I've tried looking into how to do it but the Microsoft explanation is a bit over my simple brain.
Anyone have any comments on what the problem is most likely to be as mail in general on this server seems fine in and out.