No screens showing & error (Unexpected token < in JSON at position 0)

[unclehowell]

So I don't see any screens in the dropdown and when I hit start I get the following error:
Unexpected token < in JSON at position 0

[Heath123]

Do you get Error: Couldn't find a matching codec in the console too?

[Heath123]

I think you need libx264 or libvpx, it says that at the start of the README