Hey,

same Problem here. After upgrading to OpenHAB 2.3 i receive the same errors in my /var/log/openhab2/openhab.log

2018-05-31 16:28:42.776 [ERROR] [rotocol.mqtt.MySensorsMqttConnection] - No connection to broker: mosquitto
2018-05-31 16:28:42.918 [ERROR] [rotocol.mqtt.MySensorsMqttConnection] - Failed connecting to bridge...next retry in 10 seconds (Retry No.:0)