System.Net.WebSockets.WebSocketException : Unable to connect to the remote server
---- System.Net.Http.HttpRequestException : Unknown error (0xffffffff) (corefx-net-http11.azurewebsites.net:80)
-------- System.Net.Sockets.SocketException : Unknown error (0xffffffff)

   at System.Net.WebSockets.WebSocketHandle.ConnectAsync(Uri uri, CancellationToken cancellationToken, ClientWebSocketOptions options) in /_/src/libraries/System.Net.WebSockets.Client/src/System/Net/WebSockets/WebSocketHandle.Managed.cs:line 237
   at System.Net.WebSockets.ClientWebSocket.ConnectAsyncCore(Uri uri, CancellationToken cancellationToken) in /_/src/libraries/System.Net.WebSockets.Client/src/System/Net/WebSockets/ClientWebSocket.cs:line 96
   at System.Net.WebSockets.Client.Tests.WebSocketHelper.<>c__DisplayClass4_0.<<GetConnectedWebSocket>b__0>d.MoveNext() in /_/src/libraries/System.Net.WebSockets.Client/tests/WebSocketHelper.cs:line 93
--- End of stack trace from previous location ---
   at System.Net.WebSockets.Client.Tests.WebSocketHelper.<Retry>d__5`1[[System.Net.WebSockets.ClientWebSocket, System.Net.WebSockets.Client, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a]].MoveNext() in /_/src/libraries/System.Net.WebSockets.Client/tests/WebSocketHelper.cs:line 109
   at System.Net.WebSockets.Client.Tests.WebSocketHelper.<Retry>d__5`1[[System.Net.WebSockets.ClientWebSocket, System.Net.WebSockets.Client, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a]].MoveNext() in /_/src/libraries/System.Net.WebSockets.Client/tests/WebSocketHelper.cs:line 116
   at System.Net.WebSockets.Client.Tests.WebSocketHelper.TestEcho(Uri server, WebSocketMessageType type, Int32 timeOutMilliseconds, ITestOutputHelper output) in /_/src/libraries/System.Net.WebSockets.Client/tests/WebSocketHelper.cs:line 30
   at System.Net.WebSockets.Client.Tests.ConnectTest.EchoBinaryMessage_Success(Uri server) in /_/src/libraries/System.Net.WebSockets.Client/tests/ConnectTest.cs:line 49
--- End of stack trace from previous location ---
----- Inner Stack Trace -----
   at System.Net.Http.HttpConnectionPool.ConnectToTcpHostAsync(String host, Int32 port, HttpRequestMessage initialRequest, Boolean async, CancellationToken cancellationToken) in /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs:line 1363
   at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken) in /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs:line 1268
   at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken) in /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs:line 1371
   at System.Net.Http.HttpConnectionPool.SendUsingHttp11Async(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken) in /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs:line 854
   at System.Net.Http.HttpConnectionPool.DetermineVersionAndSendAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken) in /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs:line 901
   at System.Net.Http.HttpConnectionPool.SendAndProcessAltSvcAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken) in /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs:line 906
   at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken) in /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs:line 925
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken) in /_/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/RedirectHandler.cs:line 30