It looks like I am affected by the same issue. I tried to connect to a MQTT broker (mosquitto) in my local network without sustainable success.
I tested:
- Pairing with Android / iPhone
- Mosquitto installed via deb packages
- Mosquitto running in docker
- Mosquitto running on another machine
- Nuki connected to the same subnet as the broker
- Shorter MQTT credentials
As result, the lock behaves always the same … strange. On the first look there is a connection and initial messages are sent. But this state does not persists. After a while (cannot tell whether its minutes or hours) no more updates are sent. Commands (lock/unlock) via MQTT never worked. In debugging mode of the broker, I see that the lock never sends credentials. It always “authenticate” anonymously, no matter what I set in the app.
I reported that to Nuki almost 2 month ago. But the support just asked questions I already answered. In my opinion the MQTT feature has not even reached the beta stage there are still too many “edge” cases which has not been considered. There might be exact one setup in which the MQTT stuff work, but Nuki does not communicate how that should look like. Maybe a Home Assistant instance is required I don’t have?
It is really great that Nuki tries to make the lock open for local solutions and this was actually my the feature why I bought a Nuki. But the way how the bugs with MQTT are just ignored is very sad and disappointing.