Can I please ask those of you reporting this issue to check whether your engines are in the RUN or FEATHER position? When you start the engines on the A400M they will initially go to the FEATHER position, which is where I am seeing users saying their PWR is stuck at 3.6%. Please advance the engine fuel selectors below the throttle quadrant to the RUN position for all four engines, before ensuring that the chocks are removed in walk around mode, and that the parking brake is released to see if you’re able to start taxiing! 
Thanks
The MSFS Team