I am seeing this in the log for a Homie device. System was working fine and then this just popped up. Using MQTT Explorer the Homie device is online and working just fine. Any thoughts?
2019-12-26 15:28:32.281 [hingStatusInfoChangedEvent] - 'mqtt:homie300:Queen:scene-54703' changed from ONLINE to OFFLINE (COMMUNICATION_ERROR): The connection object has not been set. start() should have been called!
MQTT experienced a few changes in the time of Nov to Dec and a few continuous integration tests that would catch errors had to be disabled. Please keep observing the log and if possible fill a bug report on Github.