I would say overkneading. But is it possible the yeast didn't proof (too hot/cold liquid)?

I think it was a yeast issue also.

Both the King Arthur and Serious Eats websites have recipes for no-knead pizza dough. They're similar. Just as with making no-knead bread (which both also have recipes for), the secret is to mix the dough with what may seem to be a tiny amount of yeast and let it rest for 18-24 hours. Meaning, you start the day before and let it sit. There's very little active time.

The yeast does the work. There's very little manipulation of the dough so it won't get tough. The resulting pizza crust is light and very tasty. Try this approach next time.

The bread machine did all the kneeding. Same as previous times. Maybe I'll let it rest longer next time?

I would try it without the bread machine. The no-knead is done just that way for a reason, to avoid the toughening of the dough from kneading. It's a process aimed at the result, not as a labor saver.

Did it puff up and rise normally? Might it simply have been overbaked? Sometimes that happens to me - just a few minutes more in the oven can make a difference.

Is it the same flour you always use? I've noticed variations in the amount of gluten in the unbleached organic flour I buy, depending on the brand - one store's seems lower/softer and another's seems higher/harder, for instance. That affects how well yeasted doughs rise. Less gluten makes for tender cookies and cakes, but it makes for denser bread, IMPE.

I would check the viability of the yeast as well.

Yes, Carol, same flour. It didn't puff up a lot.

That may be the reason, then. I'd definitely test the yeast.

I would let the dough rest or rise for an hour and a half after taking it from the bread machine, if that is how you prefer to make the dough.

Then press it into the pan and let it rise again before baking it.

When I make my dough, I allow the dough to hydrate for 20 to 30 minutes after mixing it, and then I knead it again. Then I let it rise for 1-1/2 hours before forming it into a shape for a peel.

Making the dough a day or two ahead and storing it in the fridge is also a good idea.

I make my dough, knead and let it rise in a bowl. I then take it out and press and form it into the skillet or the pizza pan, load it with toppings and bake.

I also like to hydrate my dough ... and am notorious for forgetting before I knead, but it enhances the flavor we like. I like to mix it at night, and then knead first thing in the morning before proofing in the oven for a late afternoon/evening pie. I also make enough for two ... and put half in a zip bag in the fridge for down the road.

If it didn't puff up as usual, I would also guess that the yeast was at fault...or more likely the temp of the water used. Too cool to activate it properly, or too hot and killed some of it off. I always proof my yeast regardless of directions to just add it directly to the mix.

Maybe, somehow you damaged the yeast. I have had pizza dough not rise to the occasion and have attributed it to a weak response from the yeast or some nasty evil witch with a wart on her nose.