It's the same problem which is descibed in,
in the current version (1.5.6) the real problem is not fixed, so I created this new issue.
Today we had an crash on one of our enviromental boxes:
Directly after a failover we got the following message from the InactivityMonitor "InactivityMonitor[x]: Timer Task didn't shutdown properly."
Afterwards the whole process shuts down after an UnhandledException handling. In the WriteCheck method a NullReferenceException was thrown.
It seems that during the StopMonitorThreads the timer connectionCheckTimer couldn't stop correctly and ansyncTasks exists. Directly after that the asyncTasks will be set to null -> In the currenr running WriteCheck a NullReferenceException occures.
(This problem was already commented in
AMQNET-339 as last comment from Matthew Good)