Connection problem to mongodb database

[lola850]

I follow the procedure for installation but i have the bellow issue :

[NullReferenceException: La référence d'objet n'est pas définie à une instance d'un objet.]
MongoDB.Driver.MongoServerInstance.RefreshStateAsSoonAsPossible() +70
MongoDB.Driver.Internal.MongoConnection.HandleException(Exception ex) +24
MongoDB.Driver.Internal.MongoConnection.SendMessage(BsonBuffer buffer, Int32 requestId) +191
MongoDB.Driver.Internal.MongoConnection.SendMessage(MongoRequestMessage message) +125
MongoDB.Driver.Operations.CommandOperation`1.Execute(MongoConnection connection) +206
MongoDB.Driver.MongoServerInstance.RunCommandAs(MongoConnection connection, String databaseName, IMongoCommand command) +189
MongoDB.Driver.MongoServerInstance.Ping(MongoConnection connection) +316
MongoDB.Driver.MongoServerInstance.Connect() +371
MongoDB.Driver.Internal.DirectMongoServerProxy.Connect(TimeSpan timeout, ReadPreference readPreference) +222

[MongoConnectionException: Unable to connect to server ds041160.mlab.com:41160: La référence d'objet n'est pas définie à une instance d'un objet..]
MongoDB.Driver.Internal.DirectMongoServerProxy.Connect(TimeSpan timeout, ReadPreference readPreference) +804
MongoDB.Driver.Internal.DirectMongoServerProxy.ChooseServerInstance(ReadPreference readPreference) +93
MongoDB.Driver.MongoServer.AcquireConnection(ReadPreference readPreference) +227
MongoDB.Driver.MongoCursorConnectionProvider.AcquireConnection() +26
MongoDB.Driver.Operations.QueryOperation1.GetFirstBatch(IConnectionProvider connectionProvider) +91 MongoDB.Driver.Operations.<Execute>d__0.MoveNext() +113 System.Linq.Enumerable.FirstOrDefault(IEnumerable1 source) +121
MongoDB.Driver.MongoCollection.FindOneAs(IMongoQuery query) +120
MongoDB.Driver.MongoCollection1.FindOne(IMongoQuery query) +51 MongoDB.AspNet.Identity.UserStore1.FindByNameAsync(String userName) +127
Microsoft.AspNet.Identity.UserManager2.FindByNameAsync(String userName) +56 Microsoft.AspNet.Identity.<ValidateUserName>d__4.MoveNext() +392 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 Microsoft.AspNet.Identity.<ValidateAsync>d__0.MoveNext() +266 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 Microsoft.AspNet.Identity.<CreateAsync>d__0.MoveNext() +568 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 Microsoft.AspNet.Identity.<CreateAsync>d__d.MoveNext() +483 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter1.GetResult() +28
WebApplication1.Controllers.d__15.MoveNext() in d:\Users\lbettah\Documents\Visual Studio 2015\Projects\WebApplication1\WebApplication1\Controllers\AccountController.cs:155
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +92
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
System.Web.Mvc.Async.TaskAsyncActionDescriptor.EndExecute(IAsyncResult asyncResult) +97
System.Web.Mvc.Async.<>c__DisplayClass37.b__36(IAsyncResult asyncResult) +17
System.Web.Mvc.Async.WrappedAsyncResult1.CallEndDelegate(IAsyncResult asyncResult) +10 System.Web.Mvc.Async.WrappedAsyncResultBase1.End() +49
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +32
System.Web.Mvc.Async.AsyncInvocationWithFilters.b__3d() +50
System.Web.Mvc.Async.<>c__DisplayClass46.b__3f() +225
System.Web.Mvc.Async.<>c__DisplayClass33.b__32(IAsyncResult asyncResult) +10
System.Web.Mvc.Async.WrappedAsyncResult1.CallEndDelegate(IAsyncResult asyncResult) +10 System.Web.Mvc.Async.WrappedAsyncResultBase1.End() +49
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +34
System.Web.Mvc.Async.<>c__DisplayClass2b.b__1c() +26
System.Web.Mvc.Async.<>c__DisplayClass21.b__1e(IAsyncResult asyncResult) +100
System.Web.Mvc.Async.WrappedAsyncResult1.CallEndDelegate(IAsyncResult asyncResult) +10 System.Web.Mvc.Async.WrappedAsyncResultBase1.End() +49
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +27
System.Web.Mvc.Controller.b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +13
System.Web.Mvc.Async.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) +29 System.Web.Mvc.Async.WrappedAsyncResultBase1.End() +49
System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +36
System.Web.Mvc.Controller.b__15(IAsyncResult asyncResult, Controller controller) +12
System.Web.Mvc.Async.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) +22 System.Web.Mvc.Async.WrappedAsyncResultBase1.End() +49
System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26
System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
System.Web.Mvc.MvcHandler.b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +21
System.Web.Mvc.Async.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) +29 System.Web.Mvc.Async.WrappedAsyncResultBase1.End() +49
System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +28
System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9644037
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

[rammicz]

Your error says it all:
Unable to connect to server ds041160.mlab.com:41160