Magnifica S Delonghi Only noise instead of milk foam -

Good day



I have the DeLonghi Magnifica S with milk frother nozzle.

In 50% of the cases instead of milk foam there is only an enormous noise, I don't know what the reason is.
I clean the two plastic parts daily or after each use. Then you put them on top and turn them around until they
are tight.

I know from the beginning if it works or not, because if the nozzles make an enormously horrible high and loud whistling sound, there is no foam, it just starts to

boil

the milk

.

Sometimes it helps to take everything down and put it up, but 80% of

the time it doesn't.

The next day everything goes back to normal...then again

notWhat

is defective? How does the nozzle belong up so that milk foam is produced and not a concert?