Have you tried clicking into the crossword? When it freshly loads, you have the highlight but cannot type. Click into any of the boxes, then back to where you want to be (if you want to start with 1 across) and then you should be able to type.
After changing windows and coming back, you'll have to do the same thing again.
At least that works for me.
Wesley,
I just tried that and no difference -- still no letters can be typed. That's on the MS Edge browser; and it worked fine until last week.
On Firefox, I can type the letters and they sort of slowly and haltingly appear, except for the last letter in each word, which doesn't show up until I go to the next word. Also, the highlight sometimes looks more like a green stripe across/down the boxes, rather than the usual full green. Crosswords worked fine on Firefox up until a few months ago too. I can only guess that it's because of something in the Windows updates?