Car doesn't recognize my key fob.

Batteries have been replaced and i can use all the buttons on the fob to lock, unlock, open trunk, etc. But when i walk up to the door to unlock using just my hand with fob in my pocket it doesn't do anything. I have to get fob and push the unlock button. Same thing when in the car ready to start. Foot on brake, fob in pocket, nothing happens except info panel says "key not detected, insert key". When i do, it starts right up.