Inverter and/or electric troubleshooting help needed

inverter is off NO charge or pass thru power with breaker OFF

fridge is working from NON-inverter outlet

fridge supposely worked on the inverter outlet, with generator on (before inverter failure) and from generator (no way to verify this) (was this with them at home or at time of sale, seller could have been hiding the defect inverter)?

inverter obviously NOT whole house ?
i wonder is there a sub-panel
a breaker in the main panel feeding the inverter, feeding the sub panel