I'm using .NET to download data from a URL. For most URLs it works no problem, but for one specific URL, I am getting a very weird error when I try to make the connection. Furthermore, the error only happens on the 2nd (and subsequent) attempts to make the request. The first time always seems to work.
Here is some sample code which demonstrates the problem:
string url = "https://health-infobase.canada.ca/src/data/covidLive/covid19.csv";
for (int i = 1; i <= 10; i++)
{
var req = (HttpWebRequest)WebRequest.Create(url);
// Just in case, rule these out as being related to the issue.
req.AllowAutoRedirect = false;
req.ServerCertificateValidationCallback = (object s, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) => true;
try
{
// This line throws the exception.
using (req.GetResponse()) { }
}
catch (Exception ex) {
Console.WriteLine(ex.ToString());
Console.WriteLine($"Failed on attempt {i}.");
return;
}
}
Notes:
WebRequest
and WebClient
WebClient.DownloadData()
, but it still occurs when using WebClient.OpenRead()
ServicePointManager.ServerCertificateValidationCallback
always returns true
) does not help.The stack trace when I run in .NET Core looks like this:
System.Net.WebException: The SSL connection could not be established, see inner exception. Authentication failed, see inner exception.
---> System.Net.Http.HttpRequestException: The SSL connection could not be established, see inner exception.
---> System.Security.Authentication.AuthenticationException: Authentication failed, see inner exception.
---> System.ComponentModel.Win32Exception (0x80090330): The specified data could not be decrypted.
--- End of inner exception stack trace ---
at System.Net.Security.SslStream.StartSendAuthResetSignal(ProtocolToken message, AsyncProtocolRequest asyncRequest, ExceptionDispatchInfo exception)
at System.Net.Security.SslStream.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslStream.PartialFrameCallback(AsyncProtocolRequest asyncRequest)
--- End of stack trace from previous location where exception was thrown ---
at System.Net.Security.SslStream.ThrowIfExceptional()
at System.Net.Security.SslStream.InternalEndProcessAuthentication(LazyAsyncResult lazyResult)
at System.Net.Security.SslStream.EndProcessAuthentication(IAsyncResult result)
at System.Net.Security.SslStream.EndAuthenticateAsClient(IAsyncResult asyncResult)
at System.Net.Security.SslStream.<>c.<AuthenticateAsClientAsync>b__65_1(IAsyncResult iar)
at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization)
--- End of stack trace from previous location where exception was thrown ---
at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
--- End of inner exception stack trace ---
at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpClient.FinishSendAsyncUnbuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
at System.Net.HttpWebRequest.SendRequest()
at System.Net.HttpWebRequest.GetResponse()
--- End of inner exception stack trace ---
at System.Net.HttpWebRequest.GetResponse()
at UserQuery.Main() in C:\Users\robs\AppData\Local\Temp\LINQPad6\_gifldqtg\xltrxu\LINQPadQuery:line 12
On .NET Framework, the stack trace seems to be much less useful:
System.Net.WebException: The request was aborted: Could not create SSL/TLS secure channel.
at System.Net.HttpWebRequest.GetResponse()
at UserQuery.Main() in C:\Users\robs\AppData\Local\Temp\LINQPad5\_psduzptv\dcrjhq\LINQPadQuery.cs:line 48
Update: Submitted as an issue on github: https://github.com/dotnet/runtime/issues/43682
Based on the latest in https://github.com/dotnet/runtime/issues/43682, this seems to be an OS bug in Windows. Updating Windows to the latest version makes the issue go away.