This is being looked at but in the meantime:
This is a response to the fact that the system hasn't received the Tweets.
Could be a Twitter communication issue, a server issue, limited allocation to communicating with outside services...
Other than these - or in support of this you should also check:
Log in to Twitter and go into your Profile.
Make sure your twitter is public and not protected
Make sure you have the option "Use HTTPS When possible"