Radio not ready turn on controller

Hi i have a problem setting up my controller on the px4 6c pixhawk.
iam useing radiomaster tx16s with edgetx,iam also using the tbs crossfire with the nano rx.
when i go to calibrate the controller it comes with radio not ready pls turn on controller any help with this would be appreciated.the rx is plugged into the ppm/sbusrc port of the pixhawk.
thank you