Twitter links not shortening even though Bitly is enabled

Bitly link shortening is not working. I have my Bitly login and API code entered on the AddThis site, and I have “Bitly URL Shortening for Twitter” enabled in the plugin’s Advanced Settings on the WordPress site. Any idea why the links won’t shorten or what I need to do?

Try any of these pages to test:
https://israelpalestinetimeline.org/issa-tarayra/

Thank you!