I was facing the same issue and the reason i found to keep cells inside the camera for longer time .due to this camera cells connectors got some smug and also not able to charge cells properly .
It is just like keeping for car in garage and not drving for longer time
The quick solution is open the camera cell lod and takeout the cells.
Keep the both camera and cells in direct sunlight for 1 -2 hours.and put the cells back in camera.
Mine camera is working now.