Making very small amounts of coffee

Question

I have had this machine for the past year - no problems.  I descaled it 2 months ago.  Now, when I press the "large cup" button, the machine delivers a tiny amount of coffee.  I have to press the button ~ 5 times to get a small cup of coffee out of the machine.Is there something I am missing?Is there a simple fix that will solve this, or does it need to go back to Nespresso?Just out of interest; what type of problem can cause this - valve / sensor issue?Any help appreciated.