Access dropbox file - Authentication failed because the remote party has closed the transport stream

Thank you.

It's first time that i use this tools.

I changed the Metod in POST and insered the path ( looking other example ) but i have always error 401 not autorized.

this is new cod  : 

Dim _command As String
_command = "https://api.dropboxapi.com/2/files/list_folder"

Dim Request As HttpWebRequest
Request = HttpWebRequest.Create(_command)
Request.Method = "POST"
Request.KeepAlive = True
ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 Or SecurityProtocolType.Tls12 Or SecurityProtocolType.Tls11 Or SecurityProtocolType.Tls
Request.ContentType = "application/json" ' application/x-www-form-urlencoded"
Request.UserAgent = "Mozilla/5.0 (Windows NT 6.3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.154 Safari/537.36"
ServicePointManager.SecurityProtocol = CType(48, SecurityProtocolType) Or CType(192, SecurityProtocolType) Or CType(768, SecurityProtocolType) Or CType(3072, SecurityProtocolType)
Request.AllowAutoRedirect = True

Request.Headers.Add("Authorization", "Bearer " & token)

Dim payloadLiteral = "{""Path"": ""/files/list_folder""}"

Dim payload = Encoding.UTF8.GetBytes(payloadLiteral)
Request.ContentLength = payload.Length

Using dataStream = Request.GetRequestStream()
dataStream.Write(payload, 0, payload.Length)
End Using

Try
 Using response = CType(Request.GetResponse(), HttpWebResponse)
    Using reader = New IO.StreamReader(response.GetResponseStream())
        'Return reader.ReadToEnd()
    End Using
 End Using
Catch ex As WebException
Using response = CType(ex.Response, HttpWebResponse)
    Using reader = New IO.StreamReader(response.GetResponseStream())
      Throw New Exception(reader.ReadToEnd())
    End Using
End Using
Catch ex As Exception
Throw
End Try