I have a 2015 Honda Fit with a key fob issue - the standard 3 button black remote with red panic button.
My wife's fob works perfectly as it should, lock, unlock, panic alarm, everything

My key fob suddenly stopped doing much of anything, but it is more complicated than that.
-When I press the lock button, I hear a click inside the car, sounds like a solenoid or something. However the car does not lock. Pressing it a second time does not arm the alarm as it normally would. After I press the button the light on the fob goes out briefly for half a second and then lights up again and stays lit for about 7 seconds.
-Pressing the unlock button does nothing. I hear nothing inside the car when I press the button either, unlike when I press the lock button.

Yes, I have a brand new battery inside - replaced this AM. Yes, I have tried cleaning the contacts in the remote.
Normally I would assume the remote needs to be replaced, but the fact that it seems to work (the clicking when I lock) and the light staying on for 7 seconds, I am wondering if it could be something else.

Interested to hear your thoughts
Edit: I tested it tonight, and my previous info is incorrect. The lock button is actually unlocking the car now...and the unlock and panic buttons do nothing whatsoever. Still have the issue with the fob light staying on for 7 seconds.

 

I had similar issue, but not as drastic as yours. Make sure there is nothing interfering with hatch, doors, and hood when they are in the closed position. One time I had a rope/cord that was interring with the hatch even though the hatch was shut so the key fob would not lock the doors. If that is not the problem, then I don't know what is causing your problem.