vb.net – 为什么Stripe.com返回错误(402)需要付款？

这是我创建客户的VB.net代码：

Function CreateStripeCustomer(ByVal Token As String) As String
    ''  The Stripe Account API Token - change this for testing 
    Dim STR_Stripe_API_Token As String = "sk_test_SECRET_TEST_KEY" '<-- test secret key. Change to live later.
    ''The Stripe API URL
    Dim STR_Stripe_API_URL As String = "https://api.stripe.com/v1/customers"
    ''Creates a Web Client
    Dim OBJ_Webclient As New System.Net.WebClient()
    ''Creates Credentials
    Dim OBJ_Credentials As New System.Net.NetworkCredential(STR_Stripe_API_Token,"MY_STRIPE.COM_PASSWORD")
    ''Sets the Credentials on the Web Client
    OBJ_Webclient.Credentials = OBJ_Credentials
    ''Creates a Transaction with Data that Will be Sent to Stripe
    Dim OBJ_Transaction As New System.Collections.Specialized.NameValueCollection()
    OBJ_Transaction.Add("email","PERFECTLY_VALID_EMAIL")
    OBJ_Transaction.Add("card","PERFECTLY VALID TOKEN RETURNED BY STRIPE.JS")
    ''The Stripe Response String
    Dim STR_Response As String = Encoding.ASCII.GetString(OBJ_Webclient.UploadValues(STR_Stripe_API_URL,OBJ_Transaction))
    Return STR_Response
End Function

402“需要付款”错误发生在线上：

Dim STR_Response As String = Encoding.ASCII.GetString(OBJ_Webclient.UploadValues(STR_Stripe_API_URL,OBJ_Transaction))