If you get an email from Ajar Productions that includes a YouTube link that starts with "https://youtu.be/" and have a firewall, it may get blocked. If that's the case, try changing the domain to "https://www.youtube.com/" which might be allowed to pass.
For example, if you can't reach the following:
https://youtu.be/iCLxpTZoqpY
Change the first part to be the following:
https://www.youtube.com/watch?v=iCLxpTZoqpY