Surge Guard Question

Several days ago I plugged in my new Surge Guard 30 Amp for the first time and several min later the light kept flashing red with the read out flashing "reverse polarity" then the yellow light came on and the red light kept flashing. This was after plugging in my elect cord from the TT.Unplug my TT and the light flashing reverse polarity goes off. I called the gate to ask for someone to check out the Elect Pedestal. Someone came and checked and said it was wired properly. Said the problem was in my new to me TT , 2012
Gulf Stream. I plugged back in to my TT and ever thing worked. The flashing light stating "reverse polarity" stayed on. The next morning it was off. So what do you think caused this?