Try switching brands of disk. Testing shows that some brands of DVD disks fare poorly in certain brands of players. Not sure why. Top brands to pick from include Maxell, Fuji, TDK, Sony and maybe a couple others.
I assume you aren't using bargain basement or house brands.
Anyway, whenever I encounter a disk that plays fine in one player, I know the programming is fine. If it doesn't play in another player, then the problem nearly always goes away by switching disk brands.
Ain't tecnology fun?
Bob