In heavy CPU loading condition our Web Application Get Stucked.

All threads are blocked and after 30 second in the log are added those errors:

[ERROR] - 20151005 13:15:02:97615 - RequestId=1a863907-853e-41f7-8ea7-7d84ee81db83|RequestId=1a863907-853e-41f7-8ea7-7d84ee81db83|Error on EntityController.OnException
System.TimeoutException: A timeout occured after 30000ms selecting a server using CompositeServerSelector{ Selectors = WritableServerSelector, LatencyLimitingServerSelector

{ AllowedLatencyRange = 00:00:00.0150000 }

}. Client view of cluster state is { ClusterId : "1", Type : "Sharded", State : "Disconnected", Servers : [{ ServerId: "

{ ClusterId : 1, EndPoint : "Unspecified/mywapp1:27017" }

", EndPoint: "Unspecified/mywapp1:27017", State: "Disconnected", Type: "Unknown" }, { ServerId: "

{ ClusterId : 1, EndPoint : "Unspecified/mywapp2:27017" }

", EndPoint: "Unspecified/mywapp2:27017", State: "Disconnected", Type: "Unknown" }] }.

As you can see all nodes are disconnected.

This is our connection string:

mongodb://dbuser:XXXXXXXXX@mywapp1,mywapp2/?connect=ShardRouter&maxPoolSize=500&minPoolSize=50