Sincronizzazione drone dj mini 3

non riesco a sincronizzare il dj mini 3 all’app litchi pilot

What you are asking is not clear. Waypoint missions sync between Litchi’s Mission Hub and Litchi Pilot. Litchi Pilot connects to the Mini 3. One does not sync the Mini 3 to Litchi Pilot. Which of those two things is not working?

If you mean you can not CONNECT the mini 3 to Litchi Pilot:
You have to Force Close ANY DJI app before starting Litchi Pilot.