Unable to create account at play.ht website

I’m not able to sign up for an account at play.ht using my email address. When I click “Sign up with email”, the screen says “Welcome! You are 2 steps away from getting started.” but there is no button or form to fill out.

Console shows a bunch of warnings and an error:
Failed to load resource: the server responded with a status of 404 ()
https://www.accountchooser.com/iframe.html#4277786507:1 Failed to load resource: the server responded with a status of 404 ()

Side note, there are a bunch of JS Firebase warnings.

The page I need help with: [log in to see the link]