Great but only the first use !!!

I was then two months without using 1/2.

I wanted to defrost my freezer with this steam cleaner today and it no longer works.
The steam exits accoup and without pressure.
Although I have used demineralized water the first time, I still made a cleansing "anti-scale".
Nothing helps. Steam rises a little when I press the "anti-scale" button.
I read the manual and nothing fits my fault.

What to do?
It's a pity that it is a single-use machine ...