Since we're on this topic, I want to ask a question:

How do I play video files stored in my VPS to Chromecast?

I want my mom to watch a video, from her TV, but I can't upload it to YouTube due to copyrighted content (yes, even if you set unlisted, YouTube will block it).

catt (Cast All The Things!) is your friend.

https://github.com/skorokithakis/catt

You might need a VPN as whatever is running catt must be able to connect to your chromecast and chromecast must be able to pull from whatever is running catt.

We watch all the movies this way - just cast an mp4 file. Works great on a local network.