Commented Unassigned: Getting "SOCKS5: General failure" error [2094]

I am working on code which connects using sftp and proxy. Following is my code snippet. I am getting "SOCKS5: General failure." error. Please help. (Using 4.0 binary)

Imports Renci.SshNet.SftpClient
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Dim pa As New Renci.SshNet.PasswordAuthenticationMethod("<username for site>", "<password for site")

Dim connectionInfo As New Renci.SshNet.ConnectionInfo(ftpUrl, <site port number>, "<username for site>", Renci.SshNet.ProxyTypes.Socks5, "<our proxy name>", <our proxy port number>, "<my windows username>", "<my windows password", pa)

Dim sftp As New Renci.SshNet.SftpClient(connectionInfo)
sftp.Connect()
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Comments: ** Comment from web user: drieseng **

I'm afraid I can't help you, if you can't tell me what proxy server software you're using.
If you provide this information privately, I guarantee not to make this info public.