Websocket loses connection after idling for multiple minutes

After some time of idling the client is no longer connected. Maybe increasing the timeout might help. The client already reconnects

java.net.SocketTimeoutException: Timeout on Read
	at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.onReadTimeout(AbstractWebSocketConnection.java:588)
	at org.eclipse.jetty.io.AbstractConnection.onFillInterestedFailed(AbstractConnection.java:168)
	at org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.onFillInterestedFailed(AbstractWebSocketConnection.java:534)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.failed(AbstractConnection.java:279)
	at org.eclipse.jetty.io.FillInterest.onFail(FillInterest.java:125)
	at org.eclipse.jetty.io.AbstractEndPoint.onIdleExpired(AbstractEndPoint.java:167)
	at org.eclipse.jetty.io.IdleTimeout.checkIdleTimeout(IdleTimeout.java:166)
	at org.eclipse.jetty.io.IdleTimeout$1.run(IdleTimeout.java:50)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)