I've been using headphone mode frequently on my Roku. It's been working fine, and then today it suddenly doesn't want to work. I'll get my show going, click headphone mode, and hear about 2 seconds of audio before it tells me "headphone mode turned off" and the audio cuts off. If I hit the switch to turn headphone mode on, I can watch the switch toggle back to off almost instantly after I turn it on. I uninstalled the Roku app, and I also restarted my Roku TV and it's still not working.