Aura counts reps by watching your body, so it needs to see all of you.
Prop your phone up somewhere it can see you head to toe. Leaning it against a water bottle on the floor works better than most phone stands.
Back up further than feels necessary. This is the big one. If your feet leave the frame at the bottom of a push-up, that rep doesn't count. Get your whole body in with room to spare.
Watch your lighting. Don't set up facing a window. Backlight turns you into a silhouette and the camera loses your joints.
Full range of motion. Half reps often read as one continuous movement rather than two, so you'll come up short.
Nothing between you and the phone. A chair leg or a dumbbell in the foreground can break the count.
A prompt appears on screen if you leave the frame. If you're seeing it often, move the phone further back before you start rather than adjusting mid-set.
None of this leaves your phone. Rep counting runs entirely on your device, and the camera feed is never recorded or uploaded.