Pen pressure for Elements 13 with iPad?

I'm using Photoshop Elements 13 for Mac and using my iPad Pro as a drawing tablet through the Astropad app. I had used this setup successfully for some time, but haven't done so for about a year or so. I'm trying to do so again now, but Elements isn't responding to pen pressure in any way. It doesn't seem to be a problem with the Apple pencil itself, since I've used other apps on the iPad (and on my desktop) that responded to pen pressure normally. It's only Elements that seems to have stopped recognizing pen pressure, which is pretty irksome when I'm trying to draw and control line thickness or opacity through pressure. Any ideas on possible fixes? Thank you.