Mission Planner arms but YAW PPM 2000 won't arm

If I connect the drone to MissionPlanner I can easily arm it with the ARM/Disarm button, but anything I try through PPM does not work (although I see the values are received in Setup > Mandatory Hardware > Radio Calibration.

Exactly this same setup worked with the hex file 3.1.5.

¿Any ideas?

Are the channels assigned properly? is the roll channel recognized as roll, is the pitch recognized as pitch, etc,

Are any of the channels reversed? meaning they go left when the stick moves right?

I was able to solve it, will update the original post with the solution… probably you could give me insights on way one parametrization was bad.

Original link: ArduCompter3.2.1_amp2_quad wont arm