Something similar happens to me, but in my case when I click to “Login with Twitter” nothing happens. Ate the dev console (Chrome), there’s a request to ajax-admin.php with a 500 status response (just Internal Server error on the message, nothing else).
Using WordPress 4.0, Revival Old Post 6.8.4
EDIT: forget, it had nothing to do with the plugin itself. My webserver (an Amazon EC2) didn’t have php-curl package installed.
