Error: received null username or password for unpwd check

[xxMario1995xx]

Hi,

I’m trying to use GroBro with a Growatt inverter using local MQTT (no cloud).

My problem seems to be a fundamental mismatch between Growatt’s MQTT client and Mosquitto authentication requirements.

New connection from 172.30.32.1:56766 on port 8883. error: received null username or password for unpwd check

Important details
• The Growatt mobile app does NOT allow setting a username or password for MQTT
• Username/password fields are always empty
• TLS can be enabled, but auth credentials cannot be configured
• Mosquitto rejects the connection because:

This suggests that the Growatt inverter always connects without credentials.

1.	Is Growatt local MQTT expected to work without authentication only?
2.	Is there a recommended way to run GroBro without Mosquitto authentication?
3.	Is using a separate Mosquitto instance without auth (e.g. Raspberry Pi) the intended solution?

Thank you for help!!