Hello. I am new to DJI products and drone piloting in general, and I am flying a Mavic Pro 2. However, in flight I am getting an error message in the DJI Go 4 app that says my RC signal is weak and the drone is only about 2400 feet away. Supposedly the drone can fly much farther than that...18 kilometers from what Ive read. Am I missing something somewhere? Any help or feedback would be appreciated.

You must keep the controller pointed in the direction where you are fying, use the dual band and avoid obstructions between the controller and the drone, like for example trees, walls and simmilar.

18km is the maximum travel distance, not all in one direction away from you though! Max transmitter range is up to 8km, when the drone is 120m/400' up and there are no obstructions, over flat ground.