Data Server Fails to Start with "Could not establish WebSocket connection with HOSTNAME:PORT. The target q process exited abnormally. Check for earlier errors (e.g. license or startup errors)

Symptoms

When attempting to start data server after upgrade to version 18.1 and above or new installation for versions 18.1 and above, data server fails to start with below error in watchdog.log:

{"level":"ERROR","time":"YYYY-MM-DDTHH:MM:SS.mmmZ","logger":"watchdog","caller":"Watchdog.java:652","thread":"ForkJoinPool.commonPool-worker-2","msg":"Failed to start RTS-0 engine (port=port)"}
com.appian.data.server.UnrecoverableError: Could not establish WebSocket connection with hostname:port. The target q process exited abnormally. Check for earlier errors (e.g. license or startup errors).

The rts-engine.log has the below error:

'YYYY.MM.DDTHH:MM:SS.mmm host

Cause

The 'host' at the end of rts-engine.log means unlicensed host.

Action

k4.lic requires the output of hostname command for requesting license. Compare the output for hostname command and the hostname for which license was requested. In case they don't match, request a new copy of license and deploy.

Affected versions

This article applies to Appian 18.1 and later.