I have an iPhone 6s and the latest version of iTunes (on a MacBook Pro). A few songs in my iTunes library on my computer do not appear on my iPhone, even though I have made sure that they are in the correct playlists that are set to sync with my phone. I have even tried syncing my entire library with my phone, but those songs do not appear then, either. They can be played on my laptop, but no matter what I do they do not appear on my phone. Help please?