Open the
coin accepter and clean the
coin path with a damp microfiber towel.
As young as your machine is, that shouldn't really be the problem, but someone may have inserted a gummy
coin.
One of my locations had dirty power, giving all sorts of faults. I just put an UPS in line with the power cord and no more problems. Up until then, I would have to reboot the machine to make it work correctly.
If cleaning doesn't help, try rebooting.