Another possibility; what generation iPad is it, and what type of TV?
If it’s one of the older ones that lacks a Retina (2048×1536) display and you have a 1080p HDTV, then it’s possible that you are having connectivity issues simply because 1920×1080 HDTV requires more bandwidth than the 1024×768 of older iPads because it’s trying to push ~2.6 times as much data through.