ASIForDataRequest request fails

Question

I am trying to call web service with the help of ASIHTTPREQUEST, now when webservice called it will directly go in to the RequestFailed.

Below is code with which I call the request:

-(void)Submit_Called_For_LoginApi
 {

 ASIFormDataRequest *request1;

 request1 = [ASIFormDataRequest requestWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@",STR_URL_login]]];

 request1.timeOutSeconds = 140;

 [request1 setPostValue:self.txtEmail.text  forKey:@"email"];
 [request1 setPostValue:self.txtPassword.text  forKey:@"password"];

 [request1 setPostValue:@"1"  forKey:@"device_type"];



 NSLog(@"STR_URL_login  email= %@, password=%@, device_token=%@, device_type=1",self.txtEmail.text,self.txtPassword.text);


 [request1 setDidFinishSelector:@selector(requestFinished_login:)];
 [request1 setDidFailSelector:@selector(requestFailed_login:)];


 [request1 setDelegate:self];

    [request1 startAsynchronous];

 //[request1 startSynchronous];


 }

and here is my requestFailed_login

- (void)requestFailed_login:(ASIHTTPRequest *)request
{
    NSLog(@"Request Failed %@",[request responseString]);
    [SVProgressHUD dismiss];

    [appDel UnknownError];

    return;
}

now my problem is still its not going inside RequestFinished. What i need to do to solved this problem ? what should i need to do to solve this error or problem.?