13 Corolla S Wont start, Help!

My Girlfriends 2013 Corolla S out of nowhere will not crank, as if the battery is completely dead. Even the doors will barely lock and lights will barely show any light. It will barely jump start and runs fine. I checked the battery. 12.9 Volts post to post and to random ground spots. And after sitting overnight, 12.8 volts. Alternator is putting out over 14 volts. I cleaned the battery terminals and connectors and still nothing. This car gets driven every day and has not sat. This just happened out of nowhere after a 2 minute stop at the post office. I've also checked some of the fuses and haven't found any burnt yet. If anyone could give some pointers that would be extremely appreciated, thank you.

Car has 140,000 miles.
Run a drop test from the alternator to the battery. If you're not getting around 14+ volts, then your alternator is not actually functioning properly.