If a user signs up for a message deliverer (i.e. Email Deliverer, SMS, etc) and then the message deliverer is removed from the system, the preferences still sit around, and still get processed.
KEN will create message delivery records for them still, but when it goes to deliver, it won't actually deliver b/c the registry doesn't show that old deliverer as being accurate any more, which is appropriate behavior.
The problem though is b/c that message delivery record sits around in an UNDELIVERED state, KEN will keep trying. We need to fix this by:
1.) Has a try count so that it stops trying to deliver after a certain number of attempts
2.) The message delivery record never gets created b/c the deliverer is no long registered in the system
3.) All message delivery records to be delivered to by a non-existent deliverer fail and get marked as DO NOT DELIVER or something like that after the first attempt
This was discovered by Cornell: https://jira.cornell.edu/jira/browse/CYNERGY-189