Can’t turn off camera during FaceTime calls

Everytime someone calls me on FaceTime Video or Audio, my camera is always on. The button for turning it off is disabled and I can only start FaceTime Video calls. I’ve seen other people ask about it, but they always get replies like “If you can’t use FaceTime…”, but this doesn’t apply here. I can use FaceTime, I just can’t turn off my camera. I have tried restarting my iPhone, restoring, and I have the newest iOS update. Before that, I couldn’t share my screen so I reset my iPhone and this fixed it. I tried again, but it didn’t fix it.