They recommend that you use the Universal Login page:
“We recommend implementing passwordless with Universal Login. If you are using embedded login with Lock or Auth0.js, you will need to enable custom domains for your tenant. To learn more, see Custom Domains.”
But all of their documentation for single page applications does NOT use the Universal Login.
Exactly the same issue here; we’re trying to set this up with the Universal Login but could not seem to find out how. The ‘pop-up’ flow gives CORS errors as some other topics have shown, so that does not seem as an option.
Working solution:
In the Universal Login tab, you can select a default custom template with the name ‘Passwordless’.
Sorry for the inconvenience @daniel_p! I’ll relay your feedback to appropriate team! Thank you a lot @kostas for providing the knowledge on the solution!