MQTT Engine v4.0.18 with Ignition Edge v.8.1.28


I spent whole day to configure MQTT Engine Module to work with my Ignition Edge.
The problem is that Edge can read values, but when I am trying to put some value to it, so it sets the tag to 0 value.
Finally I tried to install the older version of MQTT Engine Module, and everything works fine so, that I can read/write values
Now I use MQTT Engine of version 4.0.15 and Ignition Edge version 4.1.28

I tried Ignition version 8.1.32 also, but no luck…

Can anyone tell me if I should set up something in the Ignition Gateway to make it work with version 4.0.18 please

Thanx in Advance

I think it might be best for you to open a support ticket so we can take a look at the logs. Can you send an email to with this same information as well as the logs from the Edge and the system running MQTT Engine? Make sure you are using 4.0.18 so we can see what potential problems may be occurring in the latest version.

Sharing my experience with a similar issue:
Had intermittent MQTT engine connection issues with MQTT Engine version is 4.0.8 + Ignition Edge Version: 8.1.7
It worked well for good year or more and recently engine was disconnecting and connecting constantly I did not get any payloads on any topics.
Solution: Upgrading the MQTT Engine to 4.0.18 fixed the problem.

1 Like

Another instance was Ignition V 8.1.28 + MQTT Engine 4.0.17 was not working for me. I did restore a back up taken from v8.1.13 and restored it in v8.1.28 (not sure if this contributed to the problem). In this setup I was not able to connect to a MQTT broker at all untill I downgraded the Ignition and the Mqtt versions to the following v8.13 + MQTT Engine 4.0.13.

I had a somewhat similar issue , I was upgrading all of our gateways to 8.1.30 (34 of them) #26 was at 8.1.20 / 4.0.6 mqtt engine. I upgraded to 8.1.30 with 4.0.18 like the site says, no luck. could not get the engine to connect to any broker. we restored and tried again , no luck. We tried going back versions of the engine and found that 4.0.13 worked. On this gateway we do have several other modules, I bet there an dependency on one of them. Focusing on that this morning. Hope you find your solution.

If anyone has logs showing the connection failures I’d like to take a look at them after the upgrade. It should denote why the connection is failing. You can either post the appropriate portion of the logs here or open a ticket at

MQTT Engine 4.0.21 (b2024012618)
Ignition Edge Version: 8.1.7 (b2021060314)

And the server is available. Using other MQTT clients I have ensured that the connection has not problem

What does it show if you expand the stack trace? The reason for the failure should be shown there.

So you are getting a ‘connection timed out’. This often indicates you don’t have a valid network route to the server. Do you have a route to If pings are enabled on the server, can you ping it? Or even better, can you do a traceroute to it?

the remote server is avialable and also reachable over MQTT fx or other CLI MQTT clients.
One trigger I think might have contributed to this sudden behaviour is adding new topics to be subscribed while the MQTT client/engine was connected to the server.
From the back end is there some kind of a recommended practice to actually disable the connection of the MQTT Engine before we add new topics to subscribe ?

Different environment (related issue)

Ignition Edge Version: 8.1.7 (b2021060314)
MQTT Engine 4.0.8 (b2021071520)

Can you connect using MQTT.fx from the same machine that is getting the ‘connection timed out’? MQTT Engine can be reconfigured while it is running. It will disconnect, reconnect, and then subscribe to the configured topics.

On this other error - It is a ‘UnknownHostException’. That means name resolution is failing. You either need to configure the name of that server in your OS or have a DNS server configured and available that knows how to resolve its address. This is also a more fundamental networking issue that needs to be fixed and not really an MQTT specific issue.

Also, your MQTT Engine versions are really old. I would highly recommend upgrading per this doc: Ignition Compatibility with Cirrus Link Modules - MQTT Modules for Ignition 8.x - Confluence

Can you connect using MQTT.fx from the same machine that is getting the ‘connection timed out’?


I think it might be best for you to open a support ticket at We should be able to set up a screen sharing call and walk through these issues pretty quickly.