Fresh install of OpenHABian 3 on my RasPi 4 --> Mosquitto connection refused

[Giga522 (Jan)]

FOR an unencrypted MQTT Server

OH3 (New install) - MQTT binding failed to connect

Do you use unencrypted login at port 1883? The problem encounters because of the default setting of mosquitto v2.0+. At default settings, nobody (devices & openhab) was able to connect to the mqtt server after i reinstalled openhabian. Try to add these two lines (first line is really needed): sudo nano /etc/mosquitto/conf.d/default.conf listener 1883 allow_anonymous true Afterwards restart mosquitto.