defect

Good morning my dear connoisseurs,
my mum gave me the fully automatic machine from AEG CF250. She hadn't been using the machine for half a year because she had another one.
Yesterday I refilled everything (by the book) and looked forward to my first cup of coffee from a fully automatic machine. She was grinding, so everything was fine until she needed water to brew it. The compressor started and switched off immediately. At the same time the red light "water" lit up. :-( Then I tried to heat water for foaming, but it didn't work. The heating also works, I could feel the warming behind the grinder. I disassembled and cleaned the device according to the operating instructions. Still no water. However, I have fresh ground dry coffee in the marc container. When I asked my mum the device worked until the end.
I urgently need some advice on what I can do besides bringing the device to the customer service.

I think you need to refill the device with water... if it has been unused for so long then there is air everywhere i´n the pipes that have to go out.

Alsó turn the device on and let it heat up... when that happens draw a cup of hot water... With a bit of luck the device will work properly afterwards.

It makes sense to pull a user manual from the net... it always says what the flashing signals mean.