MQTT Distributor 4.0.3 (b2020012800): NettyMQTTHandler Ugly error on networking

Not sure if this is the right forum for this question, but I have installed an MQTT Distributor on a Windows 10 box (with Gateway installed v. 8.1). When I enable the MQTT Distributor, I get an error thrown in the logger.

Error: NettyMQTTHandler Ugly error on networking

Does anyone have some guidance on where I can find additional info on this error?

BTW: I have firewall settings open so there should not be any port blocking. Also, I ran the MQTT.FX utility locally and remotely and the Pub/Sub seems to work with this tool. But the remote MQTT Transmission will not show connected. So it is partially working.
More Detail in terms of general architecture under test:

Paging @wes0johnson

Generally that error is the result of some MQTT client sending a non-MQTT compliant packet or from an unclean disconnect of an MQTT client. I would suggest sending an email with this context and zipped up Ignition logs to so we can figure out exactly what is causing it.

Thanks Wes, I will forward what I have on this. Cheers, Chris

@wes0johnson: I think I managed to find out what the issue was with the setup. Thankfully I caught this before wasting a lot of people’s time.

I noticed that the MQTT Distributor is running on 8.1.2 version of Ignition where as the MQTT Transmission and Engine were both running on 8.1.0 versions. After I upgraded, the exception in the Logger has seemed to gone away. (I will monitor for a while to see). Does that make sense that all Ignition versions need to be the same?

Hmmm - that is odd. I can’t think of why this would be the case. There are some requirements with regard to version compatibility ( But, there isn’t anything that I can think of with your versions that would’ve caused an issue.

Let us know if anything else comes up.