AFNetworking Persisting Cookies Automatically

In: This Question it is said AFNetworking takes care of cookies automatically in the background, but in a Previous question I asked, I was having trouble keeping the session on the server that was made in php when I logged in. Once I closed(stop debugging in Xcode) the app and went back in the session was gone. The answer was to persist cookies like so to fix the problem:

NSData *cookiesData = [[NSUserDefaults standardUserDefaults] objectForKey:@"User"];
if ([cookiesData length] > 0) {
     for (NSHTTPCookie *cookie in [NSKeyedUnarchiver cookiesData]) {
           [[NSHTTPCookieStorage sharedHTTPCookieStorage] setCookie:cookie];
      }
}

This gives me an app crash when I try to do something like this. When I log in I set the NSUserDefault like so:

[[NSUserDefaults standardUserDefaults] setObject:data forKey:@"User"];
//Then synthesize

Is this the wrong way to use this? Is NSHTTPCookieStorage even my problem? Thanks.

Use the following, this is a correct way to save and load cookies that is working for me:

- (void)saveCookies{

    NSData *cookiesData = [NSKeyedArchiver archivedDataWithRootObject: [[NSHTTPCookieStorage sharedHTTPCookieStorage] cookies]];
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    [defaults setObject: cookiesData forKey: @"sessionCookies"];
    [defaults synchronize];

}

- (void)loadCookies{

    NSArray *cookies = [NSKeyedUnarchiver unarchiveObjectWithData: [[NSUserDefaults standardUserDefaults] objectForKey: @"sessionCookies"]];
    NSHTTPCookieStorage *cookieStorage = [NSHTTPCookieStorage sharedHTTPCookieStorage];

    for (NSHTTPCookie *cookie in cookies){
        [cookieStorage setCookie: cookie];
    }

}

Hope it helps!