Here is some information to help solve the issue.
E1 error code indicates a communication error between the indoor and outdoor units.
The first step would be to check that the wires are properly connected and also make sure the wires aren't crossed from the indoor to the outdoor unit.
Test your circuit board
To verify if your circuit boards are functional, you will need to test the voltage frequency between terminals L2 and S on the outdoor unit, with a multimeter set on DC ( direct current). The result should be fluctuating between - 50 v and + 50 v , If it is only fluctuating on the positive side ex: ( +10v +30v) or only on the negative side ex:( -10v - 30v) , your outdoor circuit board needs to get replaced, If the voltage fluctuation stays constant ex: ( -16v) , your indoor circuit board needs be replaced.