Getting below connection issue in couchBase sdk call for n1ql query on running app in between, When this can happen?

Getting below connection issue in couchBase sdk call for n1ql query on running app in between, When this can happen?
App was having couchbase sdk connection operation were working fine, then in between this connection issue started.
couchbase-core-io.jar |1.7.6
couchbase-java-client.jar |2.7.6
opentracing-api.jar |0.31.0
rxjava.jar |1.3.8

java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask@31940e01[Not completed, task = java.util.concurrent.Executors$RunnableAdapter@14d2ce97[Wrapped task = null]] rejected from java.util.concurrent.ScheduledThreadPoolExecutor@18b9639f[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 0]#012#011at java.base/java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2055)#012#011at java.base/java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:825)#012#011at java.base/java.util.concurrent.ScheduledThreadPoolExecutor.delayedExecute(ScheduledThreadPoolExecutor.java:340)#012#011at java.base/java.util.concurrent.ScheduledThreadPoolExecutor.schedule(ScheduledThreadPoolExecutor.java:562)#012#011at rx.internal.schedulers.NewThreadWorker.scheduleActual(NewThreadWorker.java:263)#012#011at com.couchbase.client.core.env.CoreScheduler$EventLoopWorker.schedule(CoreScheduler.java:183)#012#011at rx.internal.operators.OnSubscribeTimeoutTimedWithFallback$TimeoutMainSubscriber.startTimeout(OnSubscribeTimeoutTimedWithFallback.java:126)#012#011at rx.internal.operators.OnSubscribeTimeoutTimedWithFallback.call(OnSubscribeTimeoutTimedWithFallback.java:63)#012#011at rx.internal.operators.OnSubscribeTimeoutTimedWithFallback.call(OnSubscribeTimeoutTimedWithFallback.java:36)#012#011at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48)#012 ]…

hi @thanksForTheInfo I see you have a pretty old version of 2.7, did you try to upgrade it to the most recent version ?
As per the release notes there were some timeout issues in general that were fixed, probably you would like to start with that first ?. Also you might want to upgrade to 3.x as 2.x will reach end of life soon.