MP4 videos that I want to use in airscreen are displayed on the surface, but are not playable. There is also no video preview loaded, but only an hourglass can be seen instead. The videos were once recognized, the problem did not occur until I used a new MacBook. Unfortunately, the old MacBook is broken. Only a small number of videos are played, the majority of the videos cannot be played. Why? It would be nice if you could remedy the situation and help me. Thank you
