repl auth has been a bit problematic, but lately it stopped functioning totally. First, if you are logged in to repl.it in the browser, the repl auth iframe will not recognize this and will instead show a login screen. Second, after you log in on the login screen it merely redirects to the main repl page and does not actually "auth" the user. Third, even if the user auths correctly, no message is ever posted to the window. I tried opening in a new tab as well as in an iframe, and I do not receive any message events.