I had the same problem this morning but I still flew two batteries. After I got home, here's what I did.
1) I turned everything off.
2) Turned on Solo.
3) Turned on the controller.
4) Turned on Tablet and connected to Solo WiFi.
5) Opened the app and left it at the screen that says "Fly" and "Flight School".
6) Plugged in the GoPro4.
7) Turned on the GoPro4 (make sure it's in Video Mode).
8) Hit Fly and the live feed was there.
9) Hit record on the GoPro if you want to record your flight.
P.S - Be sure that your Solo app setting is on "Save Videos to Camera Roll" if you have an iPad