MQTT connection problem - Missing protocol

[Jellybeanz1980]

Hello,

I've installed zigbee2mqtt on homeassistant OS. I'm not able to start it. The log messages indicates communication problems with the MQTT broker:

info: z2m: Connecting to MQTT server at 192.168.16.110
error: z2m: MQTT failed to connect, exiting... (Missing protocol)
info: z2m: Stopping zigbee-herdsman...

When trying Onboarding the mqtt settings are filled, and grayed out. It's probably because that the mqtt client integration is installed, and the information is retrieved from this integration. Another integration that uses the the same broker with the same credentials is OK. The Onboarding keeps coming after restart of the homeassistant, as if the configuration is not finished due to the error.

The error log showing connection attempt tries the mqtt server without the correct link. It should be mqtt://192.168.16.110:1883. How can I force thezigbee2mqtt to use this address instead of only the IP address? I tried to implement it in the configuration.yaml file, but it is ignored somehow. Is this a bug, or am I missing something?