Why isn’t SharePlay working on my iPhone 13 Pro Max

I have friends that I FaceTime with that I would like to screen share with. But everyone is saying they can’t screen share with me. My screen share button is still gray……but I’m on the latest iOS and have the newest iPhone. I don’t understand what’s going on. I have turned off FaceTime for a little and turned it back on: I’ve signed out of FaceTime and signed back in. I’ve restarted my phone and sure SharePlay was on and it still isn’t working. I even compared my screen to my friend screens while on the phone to make sure everything looked similar. There doesn’t seem to be a problem but that one button. I need help please…….:)