I can play BluRay discs on my BluRay player and watch them on the TV no issue. However any DVD I play on the same player gives a message on the TV saying not supported.
Do some baluns only support HD or is there some mode on my BluRay I need to change?
Set your blu-ray player to 720p blu-rays tell the player the resolution to run at and if your cable length is a bit too long then lower the resolution.