I have Jetpack installed on this site - http://versiononeventures.com/
The widget was working but stopped all of a sudden.
I deactivated jetpack and installed Twitter Widget Pro instead, but couldn't get that working either. I kept getting no tweets available.
I reactivated jetpack and both subscriptions to blog and share work fine, but I cannot for the life of me activate that damn twitter username. As soon as I enter the username and hit save, it just disappears.
I would really love to display tweets on this site, but twitter is a real pain in the butt these days.
Could it be that there's a conflict somewhere? I do know that there was a new jetPack release and twitter has been messing with their API lately.