It has been a while, but I have now found the time to investigate further.
The 230v inverter flashed green/red and the fuse was sometimes blown and there was no more power from the socket.
I then removed the B pillar, first the top, which is clamped and not secured with clips. The bottom part is secured with a number of clips. It is doable in itself.
When everything was off I could clearly see the 230v inverter, which is mounted on the side of the kitchen cabinet on the inside with 4x m6 bolts.
The problem quickly became clear when I opened the 230v inverter, it seemed oxidized, perhaps water entered through the side window??
I then bought a model on Marktplaats, which differed in terms of coding, but seemed the same, but did not work. Maybe it has to do with another chip that communicates with the odb system.
Afterwards ordered from a car parts store for about 250 euros.
Built-in and working perfectly again.
I will also add some photos so that the next person has more information about what to expect.
Greetings Silvano