The inverter has an IEC plug for the output to the loads. It has an IEC socket for the input from the hookup mains.
As a test, can you remove both plug and socket from the inverter, and connect them together? This should bypass the inverter and supply hookup power direct to the 240V MH sockets. If the sockets work, then at least you know the problem is in the inverter.
As a test, can you remove both plug and socket from the inverter, and connect them together? This should bypass the inverter and supply hookup power direct to the 240V MH sockets. If the sockets work, then at least you know the problem is in the inverter.