[Plugin: Twitter Tools] Not tweeting posts, can’t login

The plugin Twitter Tools is no longer posting tweets when I post. I’ve tried changing my passoword and tesing it gives the error:

Sorry, login failed. Error message from Twitter: This method requires authentication.

Before changing the my twitter pwd I got a rate limit exceeded message, when it blatantly wasn’t a rate limit issue.

I’m now having to tweet my posts manually, which is a drag.