I updated this widget recently and my feeds immediately ceased to update. My API limit was completely fine.
Then I remembered that I had in fact had this problem before, and had been forced to use a hacked version of the plugin to overcome it. So, I reverted back to the No Backgrounds Update Fix. (I am not a Heart Internet user, but this works on my host too).
I'd suggest to the developers that it may be worth incorporating this fix into the official version of the plugin. I have now had to use this hack on 2 different hosts.
EDIT: Just noticed another post on same issue: Tweets not updating (hosting incompatibility with TLC Transients)