Sunsynk Fault Codes

SS-SUN-8.0 - Sunsynk Sun 8K HybridInverter

2x REV-2LiFE-R9-UBMS-R100-5.1 - Revov 2ndLiFE 16 Cell 51.2V100 Ah 5.1 kWh BatteryModule

For over a year, since August 2021, I've not had any problems with this professionally installed setup. Once in Sept, Oct and Nov I had F56 faults, but have had a succession of F56s recently, at various times of the night. Here is a photo of the entire fault history.

I'd really appreciate it if someone could explain the likely underlying cause and advise on what to do to deal with it. Everything in the house is on the solar except the stove top, oven and two A/C units. Geyser is controlled by GeyserWise module/element. There are two people in the house and our electricity use doesn't change much. The irritating thing is that the alarm beeps when the power goes off then A/C units ping when it comes on about 3-5(?) minutes later!!!

Thank you, Mark