Delonghi ESAM 5500.S Water circuit empty

Hello and happy new year,

Our coffee machine is giving us trouble. Delonghi itself would like a flat rate of 125 euros for the repair.
I have the hope
that with your help I can solve the problem myself :-) So:The machine makes coffee normally.
When I want to draw hot water
, it only starts and then gets stuck. Neither water nor steam

comes

out of the spout. Same with the milk container.
Both times the machine stops with the
message "Water circuit empty ...". I've been
in service mode
too.

Here the valves are rattling

and there are no errors.

When I test the pump it only buzzes (

don't

know

if this is supposed to happen

)The vaporizer doesn't make any clicking noise like with EV1 and 2 (

seemed strange to me
)I don't really know what
to pay attention
to in this service mode
.
Anybody here have any idea what
could be
causing it
?

Thanks a lot

No idea?

I would simply exchange the part in front directly at the outlet of the water but it must be possible to limit that somehow?