We have a user that sent an e-mail to three others in her department. All four users are in the same Post Office. Two of the recipients received the e-mail immediately. The third recipient didn't receive the e-mail until about 30 minutes later.

When I checked the properties of the sent item, it confirmed this. For the first two recipients the e-mail was delivered at 2:09 PM, but for the third recipient it wasn't delivered until 2:40 PM. For some reason the post office agent delayed delivery to that local user by over 30 minutes.

How can this be? What action do I need to take to fix this?

Note we're running GroupWise 8.0.1 HP1.