massaged the teat fairly vigorously with a warm wet cloth. after a couple of minutes of this, she milked fine. hope this helps.
if you do get her to milk, put some of it in a stripper cup and examine it, to make sure that she doesn't have mastitis.
fwiw, i am a beginner at this. so, take what i say as a novice opinion.
I was thinking mastitis as well.
The udder is usually hard due to pressure of backed up milk, unless there is something seriously wrong.