Several years ago, I created a sketch for an ESP8266 (NodeMCU 12E) to log-on to my local network and then switch a relay on or off in response to an ON or OFF string message on a subscribed MQTT TOPIC. All worked fine until recently, when the relay just stuck on ON, even if I manually published an ON or OFF using mosquitto_pub -h 192.168.7.245 -p 1883 -t "bathroom/fanSwitch" -m "OFF in a terminal.