Twitter is now operating as expected. Your Twitter accounts will need to be re-authenticated in order to reconnect to Connect messaging. Go to your Recipient tab and select the Social folder. Remove any Twitter pages currently displaying and then select the Twitter button at the top of the page and log in to the profile to authenticate your account. The new character limit is 280.
Connect is experiencing an issue where users cannot post to Twitter. The team is working with Twitter to resolve the issue.