VB.NET – Salesforce POST请求返回400错误请求错误

我正在尝试从Salesforce获取访问令牌.下面的代码就在昨天工作.我不知道为什么它今天不起作用.我已经尝试添加内容类型作为application / x-www-form-urlencoded,但它也没有用.当我使用curl时,我能够获得访问令牌.此外,我可以使用谷歌浏览器中的高级休息客户端获取访问令牌.任何想法为什么它返回400错误请求未知错误重试您的请求？

Imports System.Collections.Specialized
Imports System.Net
Imports System.Text

Module Module1

Sub Main()
    Dim clientId As String = "clientId"
    Dim clientSecret As String = "clientSecret"
    Dim redirectUri As String = "https://test.salesforce.com"
    Dim environment As String = "https://test.salesforce.com"
    Dim tokenUrl As String = ""
    Dim username As String = "username@salesforce.com"
    Dim password As String = "passwordtoken"
    Dim accessToken As String = ""
    Dim instanceUrl As String = ""

    Console.WriteLine("Getting a token")

    tokenUrl = environment + "/services/oauth2/token"
    Dim request As WebRequest = WebRequest.Create(tokenUrl)

    Dim values As NameValueCollection = New NameValueCollection()
    values.Add("grant_type","password")
    values.Add("client_id",clientId)
    values.Add("client_secret",clientSecret)
    values.Add("redirect_uri",redirectUri)
    values.Add("username",username)
    values.Add("password",password)

    request.Method = "POST"

    Try
        Dim client = New WebClient()
        Dim responseBytes As Byte() = client.UploadValues(tokenUrl,"POST",values)
        Dim response As String = Encoding.UTF8.GetString(responseBytes)
        Console.WriteLine(response)
        Console.ReadKey()
    Catch ex As Exception
        Console.WriteLine(ex.Message)
        Console.WriteLine("Press any key to close")
        Console.ReadKey()
    End Try

End Sub

End Module