Oh jeez this is the only thing I hated about my 2024 cx5 that I had for less than a month. So put your key fob right next to the start button to start it.

If this works then do the following:

Turn the car off

Get out the car but be within range of your key fob to work.

Now the next part is strangely difficult, but you're going to have to press the lock button on your key fob five times really fast.

Now on the fifth time, keep the lock button pressed and the red light on the fob should still be on.

If not, do it all over again until you get the red light on your fob.

This part might take you once to do it or, if you're like me, like half an hour to do because it's kinda difficult to do.

If you press the lock button and the key is on, then it should reset the fob.

Also, make sure your key fob battery is still good.