FMS is finicky. You might have to unplug your controller, shut down the software and computer, and try again.

The calibration mode is under 'joystick'.

The first time I tried FMS I had a Futaba 6EX 72mhz and it took a few attempts for the software to recognize my radio, so keep playing with it. It's probably not anything that makes sense, just a glitch in the free software.

Good luck!