Ignition http 500

We have an issue with Ignition 7.9 where it now generates an HTTP 500 from the web site.

Error 500 java.lang.NoClassDefFoundError: com/inductiveautomation/ignition/gateway/web/components/LaunchLink$Applet

Gateway scripts are still running, but the tags are generated as Unknown. The script generates a CSV file every minutes.

I have installed the latest java runtime, no isssue fixed, not sure if Ignition is re-install what yould happen to my project of config files as the backup failed (No response received from Gateway. Verify that the gateway is running.)

No idea how to read the thread dump.

Any idea?

What version of 7.9 is it? That referenced class doesn’t even exist any more in later ones.

Hi Kevin,

7.9.14 (64 bit) From the Gateway control panel, the only thing that works.


Can you get the wrapper logs and upload them? Might be easier to work with support, though I do suspect a gateway restart and/or upgrade would fix whatever is going on if you don’t care to troubleshoot.

Please help on getting the wrapper log, like how to get them.
Done the restart many times with the same result.
Upgrading? to what and will it gets the project and config without erasing them?
If possible, before an upgrade, it would be nice to get these files.


The logs are in the logs directory wherever Ignition was installed.

Call support and work with them to ensure you don’t lose any of your data.