Pages won't print 5x7 envelopes

I've tried to print on 5x7 envelopes, but Pages won't print them. I've set parameters, I've used the templates in Pages, I've tried to print to the postcard template, and nothing will print. I can print business envelopes. I've got a ten year old Windows laptop that can print, but the font selection is not good. How is it possible that Pages can't do this? I'm running a MacBook Pro with updated Big Sur and Pages.