We first experienced the problem that websocket connections were closed down unexpectedly in Jenkins  2.361.1 LTS. The problem was reported in JENKINS-69509, and Jenkins 2.375 was released subsequently to address the issue. We tried Jenkins 2.375 and found the websocket problem still there. The websocket was closed down in less than 2 hours after the build started.  Attached all the necessary logs

Reverted back to  Jenkins 2.346.3 LTS is a workaround that works for us.

How to Reproduce

• Start Jenkins 2.361.x or later with -Djenkins.websocket.pingInterval=120
• Connect a Websocket agent
  --> Notice that the websocket agent disconnect/reconnect at every ping

An interval of 120 is a way to consistently see the error. Though it should happen with any value > 30. It may happen with the default 30 but with a lower likelihood.