I implemented a Facebook login button which works perfectly fine. However, after user successfully logs in into Facebook and goes back to the app, [FBSDKAccessToken cu
You should use the following code to listen for FB access token changes, rather than listening in the delegate methods:
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(didUpdateFacebookAccessToken) name: FBSDKAccessTokenDidChangeNotification object:nil];
Please check your appDelegate class and implement all the required methods of FB SDK. I am attaching a screenshot for the same.