controller channels faulty

Hello
This is my first drone built with a rpi and navio2. I’m using the flysky fs-i6 as controller and fs-ia6 as reciever. I put a ppm encoder between the reciever and the ppm port of the navio2. I configured my drone as needed and calibrated my ESC’s manually with the reciever.I tried to calibrate my radio on the GCS (missionplanner) but when i put my throttle up al of the 6 channels moved up and only to a maximum value of 1523. So I looked on the display setting on the fs-i6 itself and it said that everything worked fine and responded like it should. I tried switching the throttle channel to another one but my results were the same.
Sorry for my bad english and thanks for the help.

Kind regards,

Matthias