System.Net.Sockets.SocketException in Function App 2.0

Question

I have function app 2.0 with set of functions with service bus and http trigger.

After deploying to our Azure production environment, we started to see below exception logged in the app insight from our function app.

Exception Type : System.Net.Sockets.SocketException

Exception Message: The SSL connection could not be established, see inner exception. Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. An existing connection was forcibly closed by the remote host

We are clueless about this exception and was following the issue - https://github.com/dotnet/core/issues/1696 and not sure by adding DOTNET_SYSTEM_NET_HTTP_USESOCKETSHTTPHANDLER=false will solve this issue.

Below is the stack trace I find it in the exception which is not triggered by my code.

System.Net.Http.HttpRequestException:
   at System.Net.Http.ConnectHelper+<EstablishSslConnectionAsyncCore>d__5.MoveNext (System.Net.Http, Version=4.2.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Threading.Tasks.ValueTask`1.get_Result (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.ConfiguredValueTaskAwaitable`1+ConfiguredValueTaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Net.Http.HttpConnectionPool+<CreateConnectionAsync>d__44.MoveNext (System.Net.Http, Version=4.2.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Threading.Tasks.ValueTask`1.get_Result (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.ConfiguredValueTaskAwaitable`1+ConfiguredValueTaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Net.Http.HttpConnectionPool+<WaitForCreatedConnectionAsync>d__49.MoveNext (System.Net.Http, Version=4.2.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Threading.Tasks.ValueTask`1.get_Result (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.ConfiguredValueTaskAwaitable`1+ConfiguredValueTaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Net.Http.HttpConnectionPool+<SendWithRetryAsync>d__39.MoveNext (System.Net.Http, Version=4.2.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Net.Http.RedirectHandler+<SendAsync>d__4.MoveNext (System.Net.Http, Version=4.2.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Net.Http.DiagnosticsHandler+<SendAsync>d__2.MoveNext (System.Net.Http, Version=4.2.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
Inner exception System.IO.IOException handled at System.Net.Http.ConnectHelper+<EstablishSslConnectionAsyncCore>d__5.MoveNext:
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.ConfiguredValueTaskAwaitable`1+ConfiguredValueTaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Net.FixedSizeReader+<ReadPacketAsync>d__1.MoveNext (System.Net.Security, Version=4.1.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Net.Security.SslState.ThrowIfExceptional (System.Net.Security, Version=4.1.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
   at System.Net.Security.SslState.InternalEndProcessAuthentication (System.Net.Security, Version=4.1.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
   at System.Net.Security.SslState.EndProcessAuthentication (System.Net.Security, Version=4.1.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
   at System.Net.Security.SslStream.EndAuthenticateAsClient (System.Net.Security, Version=4.1.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
   at System.Net.Security.SslStream+<>c.<AuthenticateAsClientAsync>b__47_1 (System.Net.Security, Version=4.1.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.ConfiguredTaskAwaitable+ConfiguredTaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Net.Http.ConnectHelper+<EstablishSslConnectionAsyncCore>d__5.MoveNext (System.Net.Http, Version=4.2.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
Inner exception System.Net.Sockets.SocketException handled at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw:

Answer 1

Thanks All. Issue has been resolved by adding this environment varaible - DOTNET_SYSTEM_NET_HTTP_USESOCKETSHTTPHANDLER=false as specified in this Issue https://github.com/dotnet/core/issues/1696 and not sure by adding