Yes, we're using Twitter to authenticate users, which means that if you can't log in at Twitter you also get the same problem at Twitt.US.
This is also affecting us when Twitter is over their load or what the blue vale is telling us
However, using Twitter to authenticate users is the best way to do things at Twitt.US, so we will continue with that.
Please note that you've not allowed to remove tweets you've received credits for.
/Bylla