Can't Place an Order

I have an AccesssToken still valid (please see image for EXP); however, whenever I placed a Buy Market order, it returned 404 bad request(see below)

Buy Function
Private Function BuyMarket(ByVal sSymbol As String, ByVal sAction As String) As Boolean
Dim urlOrder = CurServer + “/order/placeorder”

    Debug.WriteLine(" Buy from Server    " + urlOrder)
    Dim wc As System.Net.WebClient = New System.Net.WebClient
    wc.Headers.Add("Authorization", "Bearer " + txtAccessToken.Text)
    wc.Headers.Add("Content-Type", "application/json")
    wc.Headers.Add("Method", "POST")
    wc.Headers.Add("Accept", "application/json")

    Order.accountSpec = txtName.Text
    Order.accountId = txtuserId.Text
    Order.timeInForce = "FOK"
    Order.isAutomated = True

    sAction = UCase(sAction)
    If sAction = "BUY" Then
        Order.action = "Buy"
    ElseIf sAction = "SELL" Then
        Order.action = "Sell"
        Return False
    End If
    Order.symbol = UCase(sSymbol)

    Dim sJson As String = clstd.Obj2StrJson(Order)

    ' Dim data As Byte() = System.Text.Encoding.Unicode.GetBytes(sJson)
    Dim data As Byte() = System.Text.Encoding.Unicode.GetBytes(sJson)
    wc.Headers.Add("ContentLength", data.Length.ToString)
        Dim sRet As String = System.Text.Encoding.Unicode.GetString(wc.UploadData(urlOrder, data))
        Debug.WriteLine(" Return from MarketOrder = " + sRet)
        Return (True)
    Catch ex As Exception
        Debug.WriteLine("ERROR!!! Fail to submit order " + ex.Message)
        Return (False)
    End Try

End Function 'BuyMarket


Socket Openned and Ready for Login
Main message rec = o
Socket Closed

Buy from Server
‘AutoTradeMaster.exe’ (CLR v4.0.30319: AutoTradeMaster.exe): Loaded ‘C:\WINDOWS\Microsoft.Net\assembly\GAC_32\System.Data\v4.0_4.0.0.0__b77a5c561934e089\System.Data.dll’. Skipped loading symbols. Module is optimized and the debugger option ‘Just My Code’ is enabled.
Exception thrown: ‘System.Net.WebException’ in System.dll
ERROR!!! Fail to submit order The remote server returned an error: (400) Bad Request.