I have the iOS new app and just got my P3. The controller is GL300B and I can get my app to link to the remote but the message always says "Connect the Aircraft." Then when I go to the camera view it says disconnected. How do I get the aircraft to connect? I haven't even gotten this thing off the ground yet and its burning a whole in my pocket.
You know you can fly without the iThing but your P3 might need upgrading first so it's importent to get the phone/tablet working. Do you have a P3S, P3A, or P3P?
I've had a few occasions where the phone wouldn't connect with my P3P's camera and it's weird and I never figured out the cause. You can try turning on Airplane mode, make sure that WiFi is turned off, and put the P3 away from anything magnetic, then backing off about 15'-20'. Turn on the controller, turn on the phone/tablet, and then leave the remote where it is and start the P3. The times where mine wouldn't connect was always when I was close to the aircraft. But other times I can have the controller a foot away and have no problem. Also my problems were with the old Pilot app not with the Go app we use now.
Don't forget to do all the updates, an IMU calibration, and of course the compass calibration.
You may have a strong WiFi or other nearby channel interference causing the problem so try in a different area. You can look in the settings and find the channel section and see if there are any problems nearby.
And last, you have to go online after installing the Go app and register on the DJI site before it will work. I would recommend you read and reread the manual a few times before attempting to fly. It will save you from an expensive noobie crash. Choose an area to fly that is clear of trees, power lines, and other obstacles.
Hopefully some others will chime in with some suggestions.