It looks like Twitter was down and out in Australia on Friday afternoon.
Business Insider tried to use the service at between 3:08pm and 3:30pm and these were the error messages we received.
As of 3:35pm, service had been restored, with the social media company acknowledging the outage without specifying the root cause:
Earlier today some users may have experienced issues sending Tweets, this issue has now been resolved, thank you for your patience!
— Twitter Support (@Support) May 19, 2017