in our router network we often have bad latency and heavy load on the connection between the instances.
I believe that in these situations, when having SwiftMQ Explorer open, this can lead to exceptions on the router. Afterwards the Management Swiftlet appears to be dead, I have to perform a failover. Also during shutdown the mgmt swiftlet does not terminate.
I have prepared a log, beginning with the exception and then followed by a thread dump: console.log
When a Explorer connects, it sends 2 request/reply: 1. Protocol Request/Reply, 2. Connect Request/Reply. The NPE happens when a lease timeout occurs between 1 and 2. We have fixed it now. A workaround for you is to disable admin tool logging in the Management Swiftlet:
Explorer generates much traffic so it might be useful to use CLI if you administer over these connections.