Why can't I connect my iPhone to my Roku?

Episode 1494 (54:46)

Christian from Oconomowoc, WI
Roku Ultra

Christian recently bought a Lightning to HDMI cable to connect his phone to his Roku, but it doesn't work with Hulu. It only plays the sound, not the picture. Leo says it sounds like it isn't HDCP compliant. Copy Protection is probably what he's running up against. Hulu's site says it doesn't support it. There may be a workaround, though. He should try scrubbing through the timeline. According to the chatroom, 9/10 times it will bring the video back. Another solution is to log out and log back in. But if he has a Roku device, why not just use the Roku app?