Single Copter__Rudder channel not working

I am setting up a Single Copter using CC3D series Revolution as FC.

Frame class is set to 8 in latest Quadcopter firmware. Four servos are connected to the first 4 output channel of FC, and the fifth FC output is connected to the ESC for throttle (see attached screenshot).

After powering up, all the 3 channels (aileron, elevator and throttle) work, as witnessed by 2 servos moving for each of the aileron and elevator stick movement, but NO SERVO move in response to RUDDRE stick movement. Motor turns as I advance throttle.

Things I tried :–
I changed another FC (both FC work in other application), I calibrated the radio, reboot and reset everything, disabled arming (yaw stick to right) , nothing help.

Please help. Thank you in advance.