Key Fob buttons not working.

Alright, I am a new user so please excuse me if I am lacking in some details.

At the moment my remote will not lock or unlock the vehicle, although the indicator light on the remote lights up on key press. ( this vehicle is not equipped with sks )
This is a brand new key Fob (under a month old) as I had the old one replaced under warranty. I can still start the vehicle by placing the remote in the dash as usual, only the buttons don't work. It worked perfectly fine this morning, so I am not sure what the deal is.

Recently replaced:
-Key Fob itself ( about a month ago )
-12 v battery ( about 4 months ago )
- combination meter ( about a month ago )

Any clue?

 

Would the battery be a problem when it is fresh from the dealer a month ago and the red light still comes on when pressing the buttons?

 

I saw that solution here before registering an account, but I only have the tire pressure reset button, the other two sockets are empty, unless I am looking in the wrong spot. I assumed I didn't have it because it doesn't have the smart key system installed.

 

Can you believe this?? I followed the steps listed here:

Finally! How to program a non-SKS key/fob. Detailed! | PriusChat

And just used the fob itself to reprogram the locking and unlocking feature and now it works perfect! That's weird, it's almost as though it somehow lost its program to the vehicle.