WebService API鉴权，运行后提示错误 Access denied.

WebService API鉴权，以下代码应该没错啊，用JAVA调用都没问题,用户名和密码肯定没错的。运行后提示错误 Access denied.

CredentialCache credCache = new CredentialCache();
NetworkCredential netCred = new NetworkCredential();
netCred.UserName = "***";
netCred.Password = "***";
credCache.Add( new Uri(Call.Url), "Basic", netCred );
Call.Credentials = credCache;