Test a public EVSE (Electric Vehicle Supply Equipment), any L2 or 220v EVSE will push the max 3300watt (3.3KW) into the car and within 20 mins you should be over that threshold to make the L1 supplied EVSE work. If this doesn't work, id go back to the dealer.
also, look at the back of the KIA L1 Supplied EVSE, there is a little black button to the bottom, this changes the amperage level, youll notice the small lights change on the bottom of the front screen to show Low/Med/Hi amperage. test it out on the lowest or highest level to see if that helps.
2018 KIA Niro LX Plug-IN - Aurora Black Pearl
2018 KIA Sedona LX - Snow White Pearl