Mercedes 2015 ml350 - keyless go only works sporadically

I have keyless entry. When I put my hand on the car
door handle and have the key fob in my purse or
pocket, the drivers side door will not unlock.
Occasionally it does work, though. I can't figure out
why most of the time it does not respond when I
pull in the car door handle. Key fob just had battery
replaced 2 months ago. Also sometimes the vehicle
does not recognize the key and I can't turn in the
car even if the keys are sitting in the cup holder. I
have to use the unlock button first to get the car to
acknowledge the key. Any ideas or suggestions?