Gentlemen, Colleagues!
I would like to share my AEG FAVORIT 7800vi1p repair method.
Error i30 - water in the flood control system - the user manual says - turn off the water supply and call a service technician. I live in a place where service technicians are available in 3 weeks.
I searched the net, I recommend YouTube videos - there are several of them, especially in German.
My solution was to cover the bottom of the dishwasher with baking soda and pour boiling vinegar over it all. I left it for 20-30 minutes. After this time, the machine "spat out" the orange seed from the hole which I am pointing to with a screwdriver. A swollen one that was clearly blocking one of the tubes. While rinsing with soda and vinegar, various "farfocle" flowed out in the surf. A pump works in this opening, which is responsible for cleaning the dishwasher from water.
In one of the German videos, the foreman advised to remove the front panel at the bottom of the dishwasher (I have 4 self-tapping screws). After removing this mask, I found the aforementioned tray full of water that needed to be cleaned. I used kitchen paper for this. Disconnect the dishwasher from the power supply because it is full of 230V wires !!!
Not knowing the complete structure of the dishwasher, I suspect that the overflow was blocked by this stone (a small hole in the gray housing with a ball valve). Instead of being evacuated through the (clogged) drain, the water returned to the chamber in the photo through this overflow (at the moment of pressing it with a toothpick).
Illustrative photo

I started a quick program - there was no more water downstairs. I don't think the leak is anywhere.
Final advice - teach your beautiful half that your nails will not fall off from cleaning filters regularly and from rinsing dirty, dried-up plates from dried greasy food residues. If he resists, convert the cost of the foreman's visit to the number of sessions at the manicist's

(My love does not have such problems, but it disgusts these types of nooks and crannies) and in this case the machine fell on the cheese, tomato sauce and fat that I found when the i30 error appeared.