Additional information:
I reviewed the Daily Log report and found multiple occurances of the following error:
C 08:32:57.249 13 H!MSGMAN SetUp Error: MWI Mailbox<325>; COS:.
C 08:32:57.259 13 H!MSGMAN SetUp Error: MWI group <5> no lines assigned to it.
C 08:32:57.269 13 H!MSGMAN SetUp Error: Edit MAINT-Config-System-General Settings-Notification Lines.

So I looked at the System Lines configuration page and Event Group (2.2, 3.2, etc.) are all blank.
It appears I should have a 5 in all 12 lines.

Can anyone confirm that is what I need to do?