SSL HttpWebRequest in C# Could not create SSL/TLS secure channel.

Question

I am trying to POST to a remote server useing HttpWebRequest over SSL. I am getting the following error in my trace log:

"AcquireCredentialsHandle() failed with error 0X80090302."

Followed by:

"The request was aborted: Could not create SSL/TLS secure channel."

I see a lot of people having problems with this in ASP.NET and it is a problem with the ASPNET user not having privalages to the cert but I am writing a .Net windows app so I assume it is using the current user credentials to access the cert store.

The cert has a private key and is installed in the local machine store but I still can't figure out why the connection is being dropped by the remote server.

Cale · Answer

Ok so after 6 months I have solved this problem! It was several things the other server (A Webmethods Integration Server) is a little picky about what kinds of protocols it accepts. So after some fiddling around here are the two things that fixed it: ServicePointManager .SecurityProtocol = SecurityProtocolType .Ssl3; and req.ProtocolVersion = HttpVersion .Version10; So the whole code is: ServicePointManager .Expect100Continue = true ; ServicePointManager .SecurityProtocol = SecurityProtocolType .Ssl3; HttpWebRequest req = ( HttpWebRequest ) WebRequest .Create( https://websiteURL:9000 ); //Header Settings req.Method = POST ; // Post method req.ContentType = text/xml ; // content type req.KeepAlive = false ; req.ProtocolVersion = HttpVersion .Version10; //Certificate with private key X509Certificate2 cert = new X509Certificate2 ( Cert.der  Password ); req.ClientCertificates.Add(cert); req.PreAuthenticate = true ; String XML = Test Message// reader.ReadToEnd(); byte [] buffer = Encoding .ASCII.GetBytes(XML); req.ContentLength = buffer.Length; // Wrap the request stream with a text-based writer Stream writer = req.GetRequestStream(); // Write the XML text into the stream writer.Write(buffer 0 buffer.Length); writer.Close(); WebResponse rsp = req.GetResponse(); StreamReader responseStream = new StreamReader (rsp.GetResponseStream()); Hope this helps someone else in the future.

magesh raju · Answer

I am facing this  The request was aborted: Could not create SSL/TLS secure channel.  this issue. Can you please help me on this.

Sudhanshu Pandey · Answer

I faced TLS1.2 issues from many days in my project but this solution is very useful and resolved my problem. Thanks.

Mike Kisos · Answer

Hello I will make a get request (with cookie) to a website that is https can you help me please i have try it but i think there is something wrong with the certificate thanks Thanks

Mike · Answer

Hi Cale thanks to your post it only took me 3 months to fix this issue ;-) Thank you very much!!

Cale · Answer

make sure your certificate has a private key also.

Sachine Patil · Answer

Hi friend I'm facing the same issue  The request was aborted: Could not create SSL/TLS secure channel . Unfortunately your code also didn't work. Giving same error. Do I need to do any other settings of SSL on my pc ? My code works fine when I use http://abcd/service  but when I append s to http i.e. https://abcd/service I get the above error. Please reply in case of any suggestions. Regards Leo9

Petteri Vilmusenaho · Answer

I'm in the future. Your post helped me a lot! Thank you!

SSL HttpWebRequest in C# "Could not create SSL/TLS secure channel."