Keyfob Doesn't work Unless Using Physical Key first! Help

[iskoT]

Hi Guys.
I have E60 2007 5.30xi. I had Battery Issue. I bought a new battery but It gave me a lot of problem. Car was not cranking. During that time, I tried to CAS syncrnaziton. It didn't happen.
Then I replaced battery again and now Car starting and driving well.

But, keyfob doesn't works. I pull out physical key and open the door,and then Keyfob start working but after a couple minutes Car forget the keyfob again. I have spare key. it's same problem.

and IDRIVE screen does not turn on.

HELP PLEASE!
THANKS.

[TOGA]

First that comes to mind when keyfob don`t work are the universal antenna. But since you have an E60 you`re not cursed with notorious cable braking and moisture in the box. But worth checking it out by swapping. Don`t recall the location.