Some of the videos weren’t showing their thumbnail (See Image Attached), so I uploaded a screenshot taken from that video. It seemed to have worked at first, so I changed the thumbnail to the rest of my videos. Now, more videos have lost their thumbnail than what I started with. I have cleared my cache multiple times, and tested in multiple browsers. The thumbnail showed in another player I used to test. Any help would be appreciated!
P.S. The videos play perfectly.