Videos in my camera role are not loading

Anytime I try to watch a video in my camera roll or even open it will say these exact words “ unable to load video” at the top of the box that pops up in the middle of the screen and under it will say “ an error occurred while loading a higher quality Version of this video” but I’ve had the same phone with all of the videos and everything in my camera roll that I’m trying to get a hold of but ever since the update I can’t get into the old videos that I had so I’d be really appreciated if you could explain to me and help me fix it thank you.