Elevator - no servo movement

Flashed current version of Arduplane to Matek F405 Wing, using TBS Crossfire and Taranis X9D Plus Transmitter.

In Mission Planner > Radio Calibration, when moving the transmitter sticks the green bars move in accordance to the motion for all surfaces (aileron, elevator, rudder and motor). In the Servo Output screen all bars move in accordance when moving the sticks.

When moving the sticks the servos move for rudder and aileron, but no movement on the elevator servo.

I have confirmed the servo is good, swapped it with the aileron and it works. I have confirmed I have 5v going to the elevator pins,

Any ideas what I need to adjust?

Ideas: What channel is configured to be your elevator output? Is the elevator physically plugged into that channel?