Here is my source code..

SforceService binding = null;
LoginFault loginFault = new LoginFault();
LoginResult loginResult = null;

binding = new SforceService();
binding.LoginScopeHeaderValue = new LoginScopeHeader();
//binding.Url = ConfigurationManager.AppSettings["sfLoginUrl"];//Config.SforceLoginUrl;
binding.Timeout = 60 * 1000 * 10;
try
{
loginResult = binding.login(ConfigurationManager.AppSettings["ProductionEmailId"], ConfigurationManager.AppSettings["ProductionPassword"]);
binding.Url = loginResult.serverUrl;
binding.SessionHeaderValue = new SessionHeader();
binding.SessionHeaderValue.sessionId = loginResult.sessionId;
log.Debug("LoginResult Urls : "+ binding.Url);
}
catch (System.Web.Services.Protocols.SoapException exception)
{
binding = null;
log.Error( "sforceService Object not set : " + exception.Message, exception);
}

i m getting the error like  "INVALID_LOGIN: Invalid username, password, security token; or user locked out."

when i login in my developer accouont it works fine.

but in my .net (c#) application it is giving me this error.

can anybody knows what could be the problem?

should i set that Url in sforceService Object?

what difference it makes when i set it?

I deployed it in live and having the same problem.

thanks in advance!