Got error while consuming KeepAliveResponse. java.util.concurrent.TimeoutException

i am using sdk 2.6.2 , couchbase 6,0 community
and i got alof this time outs

java.util.concurrent.TimeoutException: null
at rx.internal.operators.OnSubscribeTimeoutTimedWithFallback$TimeoutMainSubscriber.onTimeout(OnSubscribeTimeoutTimedWithFallback.java:166)
at rx.internal.operators.OnSubscribeTimeoutTimedWithFallback$TimeoutMainSubscriber$TimeoutTask.call(OnSubscribeTimeoutTimedWithFallback.java:191)
at rx.internal.schedulers.EventLoopsScheduler$EventLoopWorker$2.call(EventLoopsScheduler.java:189)
at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

i am using sinlgetone bucket and i dont understant why i am getting it and what dose it mean on my production