Hello, I'm having the exact same problem outlined here: https://premium.wpmudev.org/forums/topic/events-twitter-and-google-logins-not-working
I have events+ set up. I have Google, Facebook and Twitter API keys set up. I can RSVP with Google and Facebook just fine, but when I try to RSVP with Twitter I get a pop-up window for api.twitter.com with a 404 error. Attached see the screenshots of the developer tools showing the request info.