Sometimes does not give water

Hello, I have a question about my coffee maker DeLonghi Ecam 22.110 B. Sometimes machine does not give any water. Sometimes yes, sometimes not :-) If gives some water, its about 30% less water than expected. Everytime I hear noise from waterpump, so I think waterpump works. And I also tried decalc program and it also works.

Please, I will be glad for any advice.

I tried to clean infuser with 5 min. in water but no result.

Thank you very much and have a nice day.