Chromecast on FBPlus workouts?

Anyone else having trouble casting FBPlus workouts? I've tried connecting to my TVs with an Android and a PC laptop and while it connects for a few seconds (the thumbnail appears on screen), it doesn't actually play the video. Just buffers/spins a few times then disconnects. I've tried with several videos over the past few months. I can cast the Youtube videos no problem. A bit frustrating when I'm doing an FB Program and want to listen to music on my phone while following the workout on the TV.

If anyone has any tips on how to make this work I'd appreciate it!

Edited