不确定basichttpbindpart中是否有错？

Question

当我向此网络服务发送请求以获取信息时，我遇到了问题 这是我的配置代码

<bindings>
      <basicHttpBinding>
        <binding name="Z_SI_ADVANCE_VENDORBinding" messageEncoding="Text" textEncoding="utf-8">
          <security mode="Transport">
            <transport clientCredentialType="Basic" proxyCredentialType="None"
                realm="" />
            <message clientCredentialType="UserName" algorithmSuite="Default" />
          </security>
        </binding>

这是我的代码，后面发送请求到这个webservice（http://www.xxxx.com）

    Dim epAddress As New EndpointAddress("http://www.xxxx.com")
            Dim binding As New BasicHttpBinding(BasicHttpSecurityMode.TransportCredentialOnly)
            binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Basic

            Dim client As XI_ADVANCE_VENDOR.Z_SI_ADVANCE_VENDORClient = New XI_ADVANCE_VENDOR.Z_SI_ADVANCE_VENDORClient(binding, epAddress)
Dim p_output As XI_ADVANCE_VENDOR.BAPIRETURN1
client.ClientCredentials.UserName.UserName = "xxxxx"
            client.ClientCredentials.UserName.Password = "xxxxx"
            p_output = client.Z_SI_ADVANCE_VENDOR(param1,param2) 

在调用请求完成后，它在brownser网页上显示“服务器错误”。