Remove that - it might not work as expected. It is something has needs removing, as it is a relic from the days that the MQTT Binding included its own broker. And it sounds like you’ve tried to setup two connections.
Instead, create a connection to your broker like this:
Presumably that’s because you didn’t provide your username and password in your command
When you set your Mosquitto broker up, did you choose a username and password? I’m not sure whether openhabian sets one by default…
