IPod Classic mp4 videos no longer copying to iPod

I've recently updated my iTunes which contains many mp4 files that I've always kept on my iPod. I connected my iPod to update the music I've added and the majority of my videos were deleted from my iPod, with a warning message saying that this device doesn't support these types of files. They are mp4 files that have worked on here before.

I've tried downgrading my iTunes because I assume that this is a problem on apple s end, but then my library isn't supported with older versions of iTunes.

I've also tried converting videos to a supposed iPod classic format (m4v 320 x 240) but that didn't work either.

I'm not sure if there is a solution, but if anyone else has experienced this problem and figured out how to solve it, I'd appreciate the help.

Thanks!