See screenshots in https://twitter.com/mxswd/status/1070507752575787009. Both the domains fail to register a user (the first step). Both those web pages don't load the real version of the website if you have the experimental feature disabled. The experimental feature was enabled before loading the web page. It was using a FIDO2 Yubico Security Key (the one with the little 2 printed on it).
(In reply to maxwellswadling from comment #0) > See screenshots in https://twitter.com/mxswd/status/1070507752575787009. > > Both the domains fail to register a user (the first step). > > Both those web pages don't load the real version of the website if you have > the experimental feature disabled. The experimental feature was enabled > before loading the web page. > > It was using a FIDO2 Yubico Security Key (the one with the little 2 printed > on it). I got both of them working with STP 71 and the exact same blue "2" YubiKey. From the second screenshot, it looks like that a request is pending while you issued another one. Now, our implementation is designed to only process one request at a time. Requests come at the same time internal other that the first will get "NotAllowedError: A request is pending."
*** This bug has been marked as a duplicate of bug 191517 ***