Is there any reason why, and more importantly, how the intelligent key would be de-programmed?

Couple of weeks back I changed the battery on my key FOB as it was blinking low batt. It worked for a bit after that. But now, it is not working at all.

I tried this with the spare key fob as well.

Even when I am close to the car and press the unlock/lock button, it still does not work. Even when the key fob was on low batt, this function worked.

a job for the dealer? maybe need re-programming?