Vb.net &引用；远程服务器返回错误（502）坏网关；从url下载图像文件时

我试图从网站下载图像，但它给了我错误，即（远程服务器返回错误：（502）坏网关）。我在网上搜索了很多，但没有找到确切的答案。此代码在某些网站上运行，但在少数网站上显示上述错误。 请检查我下面的代码

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Dim filename As String = Application.StartupPath
    If Not filename.EndsWith("\") Then filename &= "\"
    txtLocalFile.Text = "D:\a.jpg" 'filename & " "
    txtRemoteFile.Text = "http://bseworld.bseindia.com/eventgallery/cricket2015/19Feb2015/2.jpg"
End Sub


Private Sub btnDownload_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDownload.Click
    Application.DoEvents()
    Try
        Dim web_client As WebClient = New WebClient

        Dim wp = New WebProxy("proxy ip", proxy_port)
        wp.Credentials = New NetworkCredential("uname", "password", "domainname")
        web_client.Proxy = wp
        web_client.DownloadFile(txtRemoteFile.Text, txtLocalFile.Text)

        MessageBox.Show("Done")
    Catch ex As Exception

    End Try

    End Sub

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你能告诉我代码的哪一部分丢失了或者我必须更改吗？

我做了一些RND，最后我的代码开始工作了

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Dim filename As String = Application.StartupPath
    If Not filename.EndsWith("\") Then filename &= "\"
    txtLocalFile.Text = "" 'filename & " "
    txtRemoteFile.Text = ""
End Sub

Private Sub btnDownload_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDownload.Click
    Application.DoEvents()
    Dim web_client As WebClient = New WebClient
    Try
        web_client.UseDefaultCredentials = True
        web_client.DownloadFile(txtRemoteFile.Text, txtLocalFile.Text)
        MessageBox.Show("Done")

    Catch ex As Exception
        Dim wp = New WebProxy("Proxy IP", Proxy_port)
        wp.Credentials = New NetworkCredential("MachineUsername", "Machine Password", "Domain Name")
        web_client.Proxy = wp
        web_client.DownloadFile(txtRemoteFile.Text, txtLocalFile.Text)
        MessageBox.Show("Done")
    End Try

End Sub

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这是服务器上的一个错误。如果您拥有服务器上的代码，请查看那里。如果您没有，请联系支持团队并寻求他们的帮助。@tim。。你认为服务器上的代码有什么问题……我不知道，但服务器出了问题。这就是为什么我建议您查看服务器上的代码（和日志）（如果您拥有），或者联系相关人员。@tim。。好啊感谢您的回复…请尝试设置UserAgent。例如

web_client.UserAgent=“Mozilla/4.0（兼容；MSIE 7.0；Windows NT 5.1）”。有些网站出于安全原因需要这样做。