I have a 2013 Volt also. I have intermittent issues with my charging port. There is a known issue and bulletin about the potting on the back of early year Volts charging port electronics being to thin, cracking, and not allowing a charge. I would put my chips on that bet. I’ve been meaning to fix mine but I get it to work normally. Some nights I’ll get in the car and see it didn’t charge though. Maybe 2 times a month that’ll happen.

It’s an easy fix, you can remove the wheel and fender liner and work the old one out and install the new one.