Skid Steer ESC Won't Arm

I am trying to setup my rover as a Skid-Steer. However when I set the Servo1 to Throttle Left, and Servo3 to Throttle Right, the servo outputs do not arm.

They instead just show zeros.

Even when I manually arm my rover through MP, the values remain at zero.

The current work-around I have done is that I have to set my outputs to RCPassThrough , that way the ESC will receive a signal to arm. Afterwards without removing power I switch the outputs back to Throttle Left/Right. However this is extremely inconvenient.

Did you reboot the pixhawk after you changed it?

Clarification: It is a Navio2.

And yes, but on a fresh reboot the outputs will not send a signal except 0 and do not arm the ESCs.

If I start in RCPassThru then switch to throttle left/right after arming it works.