I am guessing a bad dogbone adapter (30/50)
The EMS determines if you are on 30 or 50 my measuring the voltage between L-1 and L-2,, If there is no voltage difference you are either on 30 amp, 20 amp or zero amp. (not plugged in)
if only one leg is receiving power from a defective dogbone, then there will be a voltage difference,, The EMS should know it's not enough but alas yours may be a bit low on the threshold (not really a problem)
See if you can borrow a different adapter and see if that works.
Home is where I park it!