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I have an application coded in VB.net that has this method of accessing Webservice, i have this error and after searching fixes i still have no luck.

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

    'ServicePointManager.Expect100Continue = False
    'ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls

    Dim request As HttpWebRequest = DirectCast(WebRequest.Create(url), HttpWebRequest)

    Dim ErrMsg As String = String.Empty

    Try

        Dim response As WebResponse = request.GetResponse()

        Using responseStream As Stream = response.GetResponseStream()
            Dim reader As New StreamReader(responseStream, Encoding.UTF8)

            Return reader.ReadToEnd()
        End Using
    Catch ex As WebException

        ErrMsg = ex.Message.ToString
        MsgBox(ErrMsg)

        Dim errorResponse As WebResponse = ex.Response
        Using responseStream As Stream = errorResponse.GetResponseStream()
            Dim reader As New StreamReader(responseStream, Encoding.GetEncoding("utf-8"))
            ' log errorText
            Dim errorText As [String] = reader.ReadToEnd()
        End Using
        Throw
    End Try

This is my code and I'm using VS2015 and Windows 10.

All help are really appreciated. TIA

wysiwyg327
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  • Maybe the webservice requires TLS 1.1/1.2? – MatSnow Oct 19 '17 at 08:24
  • Yes Mat i think the problem here circles in this code: ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls – wysiwyg327 Oct 19 '17 at 09:10
  • Thanks Mat, i tried that solution and yes it works, I created an new project targeting the 4.5 framework, the challenge now is that my Project is targeting 4.0 framework and a bunch of errors occurs when I change it to 4.5. – wysiwyg327 Oct 19 '17 at 09:18
  • https://stackoverflow.com/questions/72205024/issues-making-a-tls-1-2-request-with-net-framework-4-7/72216999#72216999 – subeesh k May 20 '22 at 06:29

3 Answers3

14

Obviously the URL you're calling requires TLS 1.1 or TLS 1.2.

You can enable TLS 1.1 or TLS 1.2 by setting the security-protocol with ServicePointManager.SecurityProtocol:

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12

.NET 4.0 supports up to TLS 1.0 while .NET 4.5 or higher supports up to TLS 1.2
For reference:

MatSnow
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    For a public portal, I had to check if stored urls still work with System.Net.WebRequest. Thereby I have noted, that calls with http crash, when the site was updated to https in the meantime (whereby a browser handles this automatically). With your answer it now works. – FredyWenger May 18 '20 at 08:56
  • Thanks it worked. I had to change Target Framework in project properties(Right click on Project on solution explorer->properties->Application) to 4.6.1 to use this – anandhu Aug 21 '20 at 17:35
0

I'm going to add something here in case it helps others. I have to support some legacy code that is written in VB.Net and targets .NET Framework 4.6.1. The same piece of code runs in both an .exe, and in IIS as a web page.

In the website, this call:

Dim dataStream As Stream = request.GetRequestStream()

would throw this exception

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

but it worked fine in the .exe.

Forcing the TLS protocol fixed it in the website. 

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12

Of course if the host ever deems TLS 1.2 unworthy I'll have to fix/recompile/redeploy, but it solved the error for now.

Matthew Allen
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-1

for vb.net 4.0 this worked for me: ServicePointManager.SecurityProtocol = DirectCast(&HC0 Or &H300 Or &HC00, SecurityProtocolType)

Champu
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