Sudden problems with 3-phase MultiPlus II 48/3000 system after more than 3 years

Hello,

I have been using my Victron system for 3 years now without any problems.
The setup is as follows:
3x MultiPlus II 48/3000 (as a 3-phase system), 2 DIY battery packs (China, EVE), each with around 14 kWh.
The cables from the public mains supply go directly to the MultiPlus units and then back into the distribution board via AC-out1 to supply the house.
I live in a single-family house with one other person.

Since 4 September, the following problem has been occurring: I have occasionally had a brief power cut in the house (around 3–4 minutes according to the records). In VictronOS, I receive the notification shown in the attached scan.

The batteries show no abnormalities (the cells are monitored individually), and there have been no unusual incidents in the house either, nor any unusual fluctuations in the power supply. The strange thing is that nobody was in the house on either of those two days (4 September and today, 8 September).

I was only able to detect the power cut in the house through the VictronOS notification and because the cooker was not showing the current time, but only had a flashing time display.

My questions to you are: Has anyone encountered a problem like this and know or suspect the solution (before I embark on a time-consuming investigation)?
And what does the “#1” before the text mean? Does it mean that device number 1 briefly failed? How and where could I read out any further errors, if necessary?
I can access all the data from VictronOS via MQTT.

Many thanks for your help.

Best regards
Heiko

You might want to check the “Remote” link on the Multis for loose screws … Recently, this was exactly what caused a Multi to suddenly shut down … the screws had apparently loosened due to the humming of the toroidal core …