No crank no start issue?

So, I have the car listed above SXT. The car has been running good, nothing out of the ordinary. I went to a friend's house to collect some money I had been owed and shut the car off when I arrived. Went back outside to turn it on to leave and the vehicle wouldn’t do anything, and I mean nothing. It won’t even crank. When I turn the key to the “on” position, my dash lights come on, headlights, all the usual things, but when I turn the key to crank the motor, it doesn’t crank and turns off all dash lights, headlights, etc. I’ve checked all fuses, none are blown, replaced battery in key fob, and my alternator isn’t but 6 months or so old. So, what else could it be?