CW much the same as already suggested. The one time that a breaker on my system tripped, I think the claimed there was a power cut (since it saw nothing on its grid connection).
I don't know about AIO but the line through the grid icon does suggest it's lost voltage, rather than merely sensing zero current through the CT clamp. Maybe. Though the fact that the meter is off (and therefore the gateway can't communicate with it) might be the problem. (On my hybrid system, the meter has a modbus interface, and the inverter asks it to interpret the raw signal from the CT clamp. Gateway may work the same way.)
Have you checked any breakers external to the unit (ie in a consumer unit between the gateway and the meter).