Q:

iTunes App getting rejected

My app has a login screen where the user logins. We are able to login on iPhone4, iPod 4, iPad 2 and iPhone5 simulator. But when we submit it to the iTunes store that time the app gets rejected. Apple mentioned that they were unable to login in the app. 
I have HMAC-SHA 256 encryption for password and at the time of login i send the encrypted password. So is there anything that, Apple has implemented for iPhone5 which dont allow the services to accept encrypted data.
I don't have a iPhone5 and i don't want to buy a iPhone5 as its too expensive. Can anyone help me with this.
This is my code:
NSMutableURLRequest *theRequest = 
[NSMutableURLRequest requestWithURL:[NSURL URLWithString:[url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:60.0];

    
    //do post request for parameter passing 

    [theRequest setHTTPMethod:@"POST"];

    
    //set the content type to JSON

    [theRequest setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];

[theRequest addValue:userName forHTTPHeaderField:@"Username"];

[theRequest addValue:sha256(passWord) forHTTPHeaderField:@"Password"];

Below are comments from Apple:

We found that your app exhibited one or more bugs, when reviewed on
  iPhone 5 running iOS 6.0.1, on both Wi-Fi and cellular networks, which
  is not in compliance with the App Store Review Guidelines.

A:

I'm always in doubt when I hear about problem with different devices, more when there is network stuff in them. Have you ever tried your app in difficult network condition? are you handling network timeouts correctly? are you using a queue to correctly dispatch all the requests? are you sure that concurrent requests respond as you expect? 
You could use the Network Link Conditioner you can download it for free from Apple site and test worst cases. I know that these are just points, but I hope they could help you.
Ciao,
andrea
[UPDATE]
Did you add reachability class??????

