Charging cable fails after rain

[Kennaway]

After a heavy rain storm, the outside ground fault outlet was tripped and the car had not charged. I disconnected everything, reset the gfci, and reconnected the cable.  The green light came on and the red fault light flashed.  I unplugged and left the cable in the sun.  After several hours I reconnected the cable. Sometimes it tripped the gfci and sometimes the green and flashing red appeared.

 

Later that day I plugged in the cable.   No green light and a solid red fault.  I tried a different gfci circuit,  and no lights at all came on.  The cable is dead.  The car is 3 years and 4 months old.  I have purchased a new cable, and put a plastic bag over the box on it in order to protect from the rain.