Catherine,
Thanks so much for your prompt response. Problem solved... with a slight modification. :)

When you pair the iPhone with the D7200, the IP address is as you said: 192.168.1.2. However, the router address is: 192.168.1.1. i.e., the last number is "1" instead of "2". It's the router ...

I am trying to connect Helicon Remote on my iPhone to my Nikon D7200. I am following these instructions:

Connecting a Nikon camera with built-in Wi-Fi unit or Wu-1 external unit
1. Make sure no other camera-related apps are running
2. Run Helicon Remote
3. Clear the Wi-Fi settings in the camera ...