Don’t get overly animated, as Twitter notify plug-in begins asking for sign-in credentials from today and it doesn’t work even if you provide with ID and password.
The reason behind that is Twitter today has made altered the process on how you sign-in to Twitter. And it doesn't provide notification that you'd need to update.
Twitter Notify has undergone an update the mesh with Twitter's latest authentication changes by Live Writer team today . You just have to install it from Windows Live Gallery and it’ll start working again. You can get it from this location.
I hope this helps...
Until next time,