The videos are all hosted on Vimeo, I believe, so I imagine it's vimeo doing the blocking. I have uBlock installed and additionally block all cookies (I have a whitelist but neither calmcode nor vimeo is on that list), and the videos work just fine.
If you could describe your browser/situation in more detail I'd love to understand what is happening. I don't need vimeo to do any cookie placing so I might be able to turn something off such that you don't need to whitelist it.
I feel a bit sorry for my initial flippant reaction. I just got a bit tired of services in recent times telling me to bugger off based on my settings and/or location.
I really like the design and the concept of the website.
Also, I really want this website to be a calm experience. That means that this sort of thing really shouldn't happen.
you get https://player.vimeo.com/video/430995866
which gives "Sorry
Because of its privacy settings, this video cannot be played here."