Question Persistent v bus over voltage fault Even with grid and loads turned off

Just newly commissioned a flex boss 21 and grid boss with wall mount battery.  (Just using it for energy storage until I can afford solar panels) Everything was running great. I happened to be standing in the room and I heard a "poof" sound come from the inverter. The inverter breaker in the grid boss tripped and the inverter turn itself off. I reset the tripped breaker and inverter still wouldn't turn on. I shut the battery off and turned it back on and the inverter finally started-  Instant fault "v bus over voltage".  And the battery backup doesn't work. Inverter won't turn on with grid power. I have 240 volts at the grid lugs in the flex boss Even when I disconnect the grid and loads and reset the inverter the code is instant. Any suggestions?