It looks like you already know its the outdoor outlet that's the problem, but I thought for posterity I should point out that the fact the car will supercharge but not charge from the UMC doesn't really eliminate the car as the source of the problem.
Supercharging(DC, high voltage) bypasses all of the rectifier/voltage-multiplier circuitry inside the car that converts the AC coming in off the HPWC/UMC/J1772 to DC, so you wouldn't know if the that circuitry has a problem or not.
Supercharging(DC, high voltage) bypasses all of the rectifier/voltage-multiplier circuitry inside the car that converts the AC coming in off the HPWC/UMC/J1772 to DC, so you wouldn't know if the that circuitry has a problem or not.