Callibration fail on accelerometers

hi
I have a 435cm hexacopter with a pixhawk 2 and I never had any issues in the last 4 months.
yesterday when we wanted to start of a new mission the radio kept telling us that we have “inconsistant” accelerometers.I tried the accel callibration on site but no succes. Back in the office I did the callibration again and so that there can not be any small moovements before hitting "any key"
again the callibration failed and the strange part is that sometimes it fails after the second step and sometimes after the last step. I do the callibration with a cable so there can not be a short disconnection between the laptop and the pixhawk2
any ideas …

hi
I did change the sd card I could callibrate again all went fine but after one flight (3min) just the same …
after the flight I unplugged the batt and when I plugged the batt back in the radio gave me the same words "inconsistant accelerometer"
any ideas …

I am sorry for my first line above … it is a 435mm :wink: hexacopter … it would be great but no