Exception[0]=System.TimeoutException: A timeout occured after 30000ms selecting a server using CompositeServerSelector{ Selectors = ReadPreferenceServerSelector{ ReadPreference = { Mode : Primary } }, LatencyLimitingServerSelector{ AllowedLatencyRange = 00:00:00.0150000 } }. 
Client view of cluster state is { ClusterId : "1", ConnectionMode : "Automatic", Type : "Unknown", State : "Disconnected", Servers : [{ ServerId: "{ ClusterId : 1, EndPoint : "Unspecified/server.company.local:27017" }", EndPoint: "Unspecified/server.company.local:27017", State: "Disconnected", Type: "Unknown", 
HeartbeatException: "MongoDB.Driver.MongoConnectionException: An exception occurred while opening a connection to the server. ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at MongoDB.Driver.Core.Authentication.MongoDBX509Authenticator.EnsureUsernameIsNotNullOrNullIsSupported(IConnection connection)
   at MongoDB.Driver.Core.Authentication.MongoDBX509Authenticator.<AuthenticateAsync>d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MongoDB.Driver.Core.Authentication.AuthenticationHelper.<AuthenticateAsync>d__1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MongoDB.Driver.Core.Connections.ConnectionInitializer.<InitializeConnectionAsync>d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MongoDB.Driver.Core.Connections.BinaryConnection.<OpenHelperAsync>d__48.MoveNext()
   --- End of inner exception stack trace ---
   at MongoDB.Driver.Core.Connections.BinaryConnection.<OpenHelperAsync>d__48.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at MongoDB.Driver.Core.Servers.ServerMonitor.<HeartbeatAsync>d__27.MoveNext()" }] }.
   at MongoDB.Driver.Core.Clusters.Cluster.ThrowTimeoutException(IServerSelector selector, ClusterDescription description)
   at MongoDB.Driver.Core.Clusters.Cluster.WaitForDescriptionChangedHelper.HandleCompletedTask(Task completedTask)
   at MongoDB.Driver.Core.Clusters.Cluster.WaitForDescriptionChanged(IServerSelector selector, ClusterDescription description, Task descriptionChangedTask, TimeSpan timeout, CancellationToken cancellationToken)
   at MongoDB.Driver.Core.Clusters.Cluster.SelectServer(IServerSelector selector, CancellationToken cancellationToken)
   at MongoDB.Driver.Core.Bindings.ReadPreferenceBinding.GetReadChannelSource(CancellationToken cancellationToken)
   at MongoDB.Driver.Core.Operations.FindOperation`1.Execute(IReadBinding binding, CancellationToken cancellationToken)
   at MongoDB.Driver.OperationExecutor.ExecuteReadOperation[TResult](IReadBinding binding, IReadOperation`1 operation, CancellationToken cancellationToken)
   at MongoDB.Driver.MongoCollectionImpl`1.ExecuteReadOperation[TResult](IReadOperation`1 operation, ReadPreference readPreference, CancellationToken cancellationToken)
   at MongoDB.Driver.MongoCollectionImpl`1.ExecuteReadOperation[TResult](IReadOperation`1 operation, CancellationToken cancellationToken)
   at MongoDB.Driver.MongoCollectionImpl`1.FindSync[TProjection](FilterDefinition`1 filter, FindOptions`2 options, CancellationToken cancellationToken)
   at MongoDB.Driver.FindFluent`2.ToCursor(CancellationToken cancellationToken)