Why the apointment slots widget is not showing up on my print preview screen?

I'm not quite sure if I understand your question correctly.

Based on the provided screenshot it seems like you're trying to print your form and the widget is not showing up in it, is that correct? I've made a test on my side and I was able to see the widget correctly on the Print Preview screen in Chrome.

Please try to clear your browser's cache and load your form again.

Let us know if this is what you're referring to or you meant something else.