关于IOS view跳转返回时出现错误

AppDelegate：

`self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
Override point for customization after application launch.
self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
self.secondView = [[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil];
self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
return YES;`

第一个viewcontroller：
` SecondViewController *second=[[SecondViewController alloc] init];
second.modalTransitionStyle=UIModalTransitionStyleFlipHorizontal;
[self presentViewController:second animated:YES completion:^{}];`

第二个：
[self dismissViewControllerAnimated:YES completion:^{}];

出现的错误：
Thread 1:Program received signal : "SIGABRT"

xib文件我都有连线