The login with Facebook and Twitter buttons are not working

I created an event and when I click “I’m attending’ it shows four options to login/register. The ‘Login with Facebook’ button doesn’t do anything, nothing pops up, nothing changes. The ‘Login with Twitter’ does bring up a Twitter pop up window, briefly flashes the login/password fields but almost immediately switches to the “Whoa there! There is no request token for this page…” message.

I’ve looked at the settings and I think I’ve done everything that seems obvious to me but evidently I’ve missed something. Any ideas please??

p.s. By the way…why can’t I upload a picture here but I can once the thread is started? Just curious!