When I try visiting the following page and clicking the "Create Developer Account" button in Step 2, a modal loads and then disappears immediately.
Page: https://developers.facebook.com/docs/apps/register
Console Errors: [Error] Failed to load resource: the server responded with a status of 404 (HTTP/2.0 404) (dialog, line 0)
go here https://developers.facebook.com/docs/facebook-login/review
after you log in. It should say "Get Started" click on it and it will allow you to create a developer account that way.