App crashes on [TestFlight takeOff:@""] in iOS 6.1.2

I have TestFlight SDK integrated into my iOS app. In iOS 6.1.2, sometimes the app crashes for the first-time app launch at TestFlight's -takeOff: method. ``` - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions: (NSDictionary *)launchOptions { #ifdef TESTING [TestFlight takeOff:@"MY_TESTFLIGHT_TEAM_TOKEN"]; [TestFlight setDeviceIdentifier:[[UIDevice currentDevice] uniqueIdentifier]]; #endif // Override point for customization after application launch. ProductListViewController *products=[[ProductListViewController alloc] initWithNibName:@"ProductListViewController" bundle:nil]; UINavigationController *navigationController=[[UINavigationController alloc] initWithRootViewController:products]; [products release]; navigationController.toolbarHidden = YES; navigationController.navigationBarHidden = YES; self.rootViewController = navigationController; [self.window setRootViewController:rootViewController]; [navigationController release]; [self.window makeKeyAndVisible]; return YES; } ``` Any help is greatly appreciated. Thanks