通过VB.net从URL复制数据

Question

这是我用来将一些数据从URL复制到文本文件的代码：

Imports System.Net
Imports System.IO

Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim request As WebRequest = WebRequest.Create("https://01hw860645vm7/piwebapi/streams/P0RCrLRNEwjUSpQKLB67jLng60cAAAMDFIVzg2MDY0NVZNN1xBR0lfQ1VSUkVOVA/value")
        Dim response As HttpWebResponse = CType(request.GetResponse(), HttpWebResponse)
        Dim datastream As Stream = response.GetResponseStream
        Dim reader As New StreamReader(datastream)
        Dim strdata As String = reader.ReadToEnd
        Dim file As System.IO.StreamWriter
        file = My.Computer.FileSystem.OpenTextFileWriter("C:\Users\1212832\Desktop\Test.txt", True)
        file.WriteLine(strdata)
        file.Close()
        TextBox1.Text = strdata
    End Sub
End Class

我收到以下错误：＆＃34;底层连接已关闭：无法为SSL / TLS安全通道建立信任关系。＆＃34; 我甚至在app.config中编写了这个脚本：

<system.net>
    <defaultProxy useDefaultCredentials="true"/>
    </system.net>

但仍然没有结果。请帮忙。