Getting a SequenceNumberException

Ignition Modules
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1

Hi,

I am seeing SequenceNumberExceptions in the logs on the Ignition Gateway running the MQTT Engine and MQTT Distributor modules.
I have another Ignition Gateway running the MQTT Transmission module publishing into my broker using SSL.
I am seeing the following error:
com.cirruslink.common.sparkplug.util.exception.SequenceNumberException: For Group="SomeGroup" and Edge Node="SomeEdgeNode" - Message Sequence number ERROR: expected=3 but received=2
Anyone knows how to resolve this issue? And why it is appearing in the first place other than something is being received out of order?

I have tried restarting all the modules, deleting any tags within the MQTT Engine, Disabling and Enabling the transmitter. But nothing seems to fix this issue.

Thanks!

2

There are a number of reasons this can occur. Take a look at the following troubleshooting document: I have data that is toggling between stale and healthy at my subscribing MQTT Client - MQTT Modules for Ignition 8.x - Confluence

1 Like
3

I was getting this error, among a lot of other disconnect issues, and the issue was resolved by changing the network adapter properties on the computer running the Transmission Module. Taking the MTU down to 1350 from the default of 1500 resolved this issue completely for me. I didn’t see this in the troubleshooting document so if none of those solve your issue maybe give this one a try. This was a mixture of communication methods though (local WISP, AT&T, and 900 MHz radios) so it may not apply to your situation.