Huh, that's really odd. Do other embedded games have the same issues? What browser are you using?
162 days ago(+1)
I had a similar issue, but after disabling my ad blockers for this page, the game loaded. I hope that helps!
if that doesn't help , it would be nice to see if there is any output in the console
*( mostly F12 on most browsers chrome or firefox, or ctrl+shift+i )
there should be an error report or log
it can be that your browser or your machine (gpu or the gpu drivers) doesn't support/recognize webgl2
guess that could happen also on older tablets or smrtphones
that also happens to me because i refuse to upgrade working hw :D but well that is me :)