Only able to login with Twitter and can't logout again


I'm only able to login and comment via Twitter and to logout I have to delete the cookie and refresh the page. Plus, shouldn't the page should automatically reload, or refresh by Ajax, after logging in? As I have to refresh the page for that as well.

I also can't comment or login via Facebook or Google either. The Facebook button jumps to the top of the page, whereas the Google button just doesn't respond at all.

I've already tried deactivating all other plugins and tested it in Chrome and Safari and it's made no difference either way. I've also triple checked the api and callback urls for both Twitter and Facebook which are correct.

Can you think of anything I might be doing wrong?