VB.NET Example

Imports System.Net
Imports System.Text

Module Main
	Sub Main()
		Dim url As String = "https://test.factorsnetwork.com/api/creditors/f386c06a-ff8f-42e9-946e-a9e88fd3eaed/data/2017-03.json"
		Dim username As String = "USERNAME"
		Dim password As String = "PASSWORD"
		Dim file As String = IO.Path.GetFullPath("FULL_PATH_TO_FILE")

		'You should not need this in production.
		ServicePointManager.ServerCertificateValidationCallback = Function(sender, cert, chain, sslPolicyErrors) True

		Dim authInfo As String = username & ":" & password
		authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo))
		Using client As New WebClient()
			client.Headers.Add("Authorization", "Basic " & authInfo)
			Dim data As Byte() = client.UploadFile(url, "POST", file)
			Dim response As String = Encoding.UTF8.GetString(data)
			Console.WriteLine(response)
		End Using
		Console.WriteLine("Press any key to exit.")
		Console.ReadKey()
	End Sub
End Module