we have a single phase backup system with two 10 KVA Quattro’s which has been operated since 2015.
Suddenly when the grid shut down and come back the master has the error as shown in the attached video.
Then at the next time when the grid shut down, there is no power from the inverter but when restarting the inverters the system goes fine and so on when the grid come back.
I tried to make it as the slave, but it shows an overload alarm and has no power.
I updated all the units to the latest version, but no change.
The error appear even no load connected.