Like a few other people, I have the bug with this plugin whereby the tweets are not updating.I'm using the latest version (2.3.3).
The ONLY way I can get the latest tweets to appear is to change the number of tweets shown. Howvere this only lasts for a short while because as soon as I make a new tweet, the plugin no longer updates itself.. it just shows the same tweets as whatever the date was when I made the "number of tweets" selection.
This person here explains it best:
and this person at the end:
The plugin forum is closed so i can't comment there.