We have a single Exchange 2010 box start to show some weird behavior. A couple users have reported email delays recently. After run get-messagetrackinglog command, I notice all the activities in the log contains only two eventid: NOTIFYMAPI and SUBMIT. And Under "Recipients" column, there is only "{}", blank, no recipients address at all for all the messages in the log. I tried a couple different time windows and get the same thing.
Look back the message tracking log I captured around 1 year back, this is definitely not the case. I can see there were "RECEIVE, RESOLVE, DELIVER, SEND..." events. For some reason, Exchange is only doing two types of activities: NOTIFYMAPI and SUBMIT...
So far send and receive emails...