My last 2 flights ended with no WiFi signal and a RTH. Last flight I was less than 400 feet away. Even as the drone went in to auto landing and I was only a few feet way still no signal. I really don't like doing a RTH unless I absolutely have to. Once I rebooted every thing all was fine. I'm using a Google Nexus with the Dji go app. Defective or just interference?