I have a Phantom 3 Professional.  Have not had a problem till recently.  RC will not connect and is flashing red light.  The manual indicate RC error, but no remedy.  I found tutorials on UTube suggesting a reset by pushig C1, C2, record and then the rotory camera settings wheel. The red light stops flashing and goes blue, then I immeidately push the link button on the aircraft and RC light flashes blue, but never connects.  I have also tried the Link RC button on the Go App.  How do I get the RC out of error mode.  Very frustrated.

Yes you possibly need to do a "Reset" of the RC and then re-link it to the AC. What you described was not exactly right, Resetting the controller and linking to the drone are two separate actions.

Reset the RC:

With RC OFF, press and hold C1 & C2 at the back of the RC and the shutter button and keep them pressed while turning the RC on.

To LINK the RC/AC -

Turn on the AC and RC and press the Link Button on the AC. This will turn RED waiting to link

On the RC Press C1 & C2 and the Record button, the RC should BEEP.

Let go the three buttons and pree the WHEEL on the RH side of the RC. The LH light on the RC should turn BLUE and the controiller will BEEP - . .   - . .  - . . (D in morse code)

The RC will stop beeping and the Link button on the AC will turn GREEN if the link was successful.

Alternately:

• Turn on the remote controller and connect controller to the mobile device you use to fly with.
• Launch DJI Pilot app.
• Turn on the aircraft Intelligent Flight Battery.
  

4.  On remote controller enter “Camera” and tap on the image of a remote controller and five bars.

5. Locate the linking button on the side of the aircraft and press it, it will start blinking.

The Remote Controller Status Indicator will display solid green once the remote controller is successfully linked to the aircraft.

Hi. I am sorry for the trouble this has caused. With regards to this concern. Kindly please try to refresh the firmware of the remote controller by using the firmware from this link. After completing this process please follow the steps provided by cheddar-man at post #2. Please keep us posted for further assistance. Thank you.