I am getting this issue with latest C# driver version 1.8.1 frequently while I run even simple query on a large collection.

However this does not generate in all cases and it works sometimes but fails sometimes which is really frustrating.

The mongo server is on Amazon Ec2 ubuntu instance and .net app is on another EC2 server.

Tried Sevres fixes like connectiontimeout,sockettimeout etc but not able to fix this.

Unable to connect to the server ec2-143-39-225-37.us-west-1.compute.amazonaws.com:27017.
at MongoDB.Driver.Internal.DirectMongoServerProxy.ChooseServerInstance(ReadPreference readPreference) in c:\projects\mongo-csharp-driver\MongoDB.Driver\Communication\Proxies\DirectMongoServerProxy.cs:line 115
at MongoDB.Driver.MongoServer.AcquireConnection(ReadPreference readPreference) in c:\projects\mongo-csharp-driver\MongoDB.Driver\MongoServer.cs:line 935
at MongoDB.Driver.MongoCollection.Update(IMongoQuery query, IMongoUpdate update, MongoUpdateOptions options) in c:\projects\mongo-csharp-driver\MongoDB.Driver\MongoCollection.cs:line 1589

Please help asap.