Pixhawk 2.4.8 with frsky L9R

Iam working on hexacopter and iam using a pixhawk 2.4.8 with a frsky l9r rc remote
I have a problem with calibrate remote with pixhawk
Iam using Qground controll
When iam connect pixhawk to Qground every thing are okay but when i connect the battery the rc don’t work i saw the channels move’s on Qground but it’s dosent make any move in real
I can’t control my hexacopter because of that problem i can’t make it fly or arming it or calibrate ESC so if any one could help or tell me where are the problem i will be thankful