And one day, the Word Count didn't work anymore

Hello to everyone,
I really enjoy using Scrivener and I have discovered the Stats and word count for the session and for the document.
I chose a goal of 750 words and every day, I was pleased to write my 750 words until… today !
It doesn’t work anymore. I’m writing but the counter (under the name of the document) still says “0 words” (and it’s not working also for the total number of words of the project).
I’ve closed scrivener, turned it on again but it’s still frozen.
The counter at the bottom of the document is working but not the one at the top (with the progress bar).
How could I turn it on again ?
Thanks for your answer,

Stephane