com.mongodb.MongoSocketException: ......: System error	
at com.mongodb.ServerAddress.getSocketAddresses(ServerAddress.java:211)
	at com.mongodb.connection.netty.NettyStream.openAsync(NettyStream.java:109)
	at com.mongodb.internal.connection.InternalStreamConnection.openAsync(InternalStreamConnection.java:152)
	at com.mongodb.internal.connection.UsageTrackingInternalConnection.openAsync(UsageTrackingInternalConnection.java:57)
	at com.mongodb.internal.connection.DefaultConnectionPool$PooledConnection.openAsync(DefaultConnectionPool.java:404)
	at com.mongodb.internal.connection.DefaultConnectionPool.openAsync(DefaultConnectionPool.java:207)
	at com.mongodb.internal.connection.DefaultConnectionPool.getAsync(DefaultConnectionPool.java:158)
	at com.mongodb.internal.connection.DefaultServer.getConnectionAsync(DefaultServer.java:105)
	at com.mongodb.binding.AsyncClusterBinding$AsyncClusterBindingConnectionSource.getConnection(AsyncClusterBinding.java:146)
	at com.mongodb.async.client.ClientSessionBinding$SessionBindingAsyncConnectionSource.getConnection(ClientSessionBinding.java:140)
	at com.mongodb.operation.OperationHelper.withAsyncConnectionSource(OperationHelper.java:611)
	at com.mongodb.operation.OperationHelper.access$200(OperationHelper.java:63)
	at com.mongodb.operation.OperationHelper$AsyncCallableWithConnectionAndSourceCallback.onResult(OperationHelper.java:631)
	at com.mongodb.operation.OperationHelper$AsyncCallableWithConnectionAndSourceCallback.onResult(OperationHelper.java:619)
	at com.mongodb.internal.async.ErrorHandlingResultCallback.onResult(ErrorHandlingResultCallback.java:49)
	at com.mongodb.async.client.ClientSessionBinding$WrappingCallback.onResult(ClientSessionBinding.java:208)
	at com.mongodb.async.client.ClientSessionBinding$WrappingCallback.onResult(ClientSessionBinding.java:196)
	at com.mongodb.binding.AsyncClusterBinding$1.onResult(AsyncClusterBinding.java:120)
	at com.mongodb.binding.AsyncClusterBinding$1.onResult(AsyncClusterBinding.java:114)
	at com.mongodb.internal.connection.BaseCluster$ServerSelectionRequest.onResult(BaseCluster.java:440)
	at com.mongodb.internal.connection.BaseCluster.handleServerSelectionRequest(BaseCluster.java:304)
	at com.mongodb.internal.connection.BaseCluster.selectServerAsync(BaseCluster.java:160)
	at com.mongodb.internal.connection.AbstractMultiServerCluster.selectServerAsync(AbstractMultiServerCluster.java:54)
	at com.mongodb.binding.AsyncClusterBinding.getAsyncClusterBindingConnectionSource(AsyncClusterBinding.java:114)
	at com.mongodb.binding.AsyncClusterBinding.getReadConnectionSource(AsyncClusterBinding.java:99)
	at com.mongodb.async.client.ClientSessionBinding.getReadConnectionSource(ClientSessionBinding.java:58)
	at com.mongodb.operation.OperationHelper.withAsyncReadConnection(OperationHelper.java:558)
	at com.mongodb.operation.FindOperation.executeAsync(FindOperation.java:764)
	at com.mongodb.async.client.OperationExecutorImpl$1$1.onResult(OperationExecutorImpl.java:88)
	at com.mongodb.async.client.OperationExecutorImpl$1$1.onResult(OperationExecutorImpl.java:76)
	at com.mongodb.async.client.OperationExecutorImpl.getReadWriteBinding(OperationExecutorImpl.java:179)
	at com.mongodb.async.client.OperationExecutorImpl.access$200(OperationExecutorImpl.java:45)
	at com.mongodb.async.client.OperationExecutorImpl$1.onResult(OperationExecutorImpl.java:74)
	at com.mongodb.async.client.OperationExecutorImpl$1.onResult(OperationExecutorImpl.java:68)
	at com.mongodb.async.client.ClientSessionHelper.createClientSession(ClientSessionHelper.java:63)
	at com.mongodb.async.client.ClientSessionHelper.withClientSession(ClientSessionHelper.java:49)
	at com.mongodb.async.client.OperationExecutorImpl.execute(OperationExecutorImpl.java:68)
	at com.mongodb.async.client.MongoIterableImpl.batchCursor(MongoIterableImpl.java:167)
	at com.mongodb.async.client.MongoIterableSubscription.requestInitialData(MongoIterableSubscription.java:46)
	at com.mongodb.async.client.AbstractSubscription.tryRequestInitialData(AbstractSubscription.java:167)
	at com.mongodb.async.client.AbstractSubscription.request(AbstractSubscription.java:90)
	at org.mongodb.scala.ObservableImplicits$BoxedSubscription.request(ObservableImplicits.scala:494)
	at org.mongodb.scala.internal.FoldLeftObservable$$anon$1$$anon$2.request(FoldLeftObservable.scala:42)
	at org.mongodb.scala.ObservableImplicits$ScalaObservable$$anon$2.onSubscribe(ObservableImplicits.scala:367)
	at org.mongodb.scala.ObservableImplicits$ToSingleObservable$$anon$3.onSubscribe(ObservableImplicits.scala:445)
	at org.mongodb.scala.internal.SubscriptionCheckingObserver.onSubscribe(SubscriptionCheckingObserver.scala:28)
	at org.mongodb.scala.internal.MapObservable$$anon$1.onSubscribe(MapObservable.scala:28)
	at org.mongodb.scala.internal.SubscriptionCheckingObserver.onSubscribe(SubscriptionCheckingObserver.scala:28)
	at org.mongodb.scala.internal.FoldLeftObservable$$anon$1.onSubscribe(FoldLeftObservable.scala:47)
	at org.mongodb.scala.internal.SubscriptionCheckingObserver.onSubscribe(SubscriptionCheckingObserver.scala:28)
	at org.mongodb.scala.Observer.onSubscribe(Observer.scala:85)
	at org.mongodb.scala.Observer.onSubscribe$(Observer.scala:85)
	at org.mongodb.scala.internal.SubscriptionCheckingObserver.onSubscribe(SubscriptionCheckingObserver.scala:21)
	at com.mongodb.async.client.MongoIterableSubscription.<init>(MongoIterableSubscription.java:40)
	at com.mongodb.async.client.Observables$1.subscribe(Observables.java:47)
	at org.mongodb.scala.ObservableImplicits$BoxedObservable.subscribe(ObservableImplicits.scala:478)
	at org.mongodb.scala.FindObservable.subscribe(FindObservable.scala:344)
	at org.mongodb.scala.internal.FoldLeftObservable.subscribe(FoldLeftObservable.scala:27)
	at org.mongodb.scala.internal.MapObservable.subscribe(MapObservable.scala:25)
	at org.mongodb.scala.ObservableImplicits$ToSingleObservable.subscribe(ObservableImplicits.scala:437)
	at org.mongodb.scala.ObservableImplicits$ScalaObservable.headOption(ObservableImplicits.scala:359)
	at org.mongodb.scala.ObservableImplicits$ScalaObservable.head(ObservableImplicits.scala:345)
	at org.mongodb.scala.ObservableImplicits$ScalaObservable.toFuture(ObservableImplicits.scala:337)