shows only 2 results

Hi, my name is Marco, I love this plugin but in my site it desn’t work properly.
my site is http://www.louisettelibrirari.it/novita/
I have installed predictive search and it’s in a widget on the right.
The problem is that it doesn’t show all result it should.
I have set the widget to 6 results. If I make a test with the word “fotografia” which is also a product tag, predictive search only give 2 results. The tag “fotografia” is present in 137 products and predictive search only gives 2 results.
Can anybody help?
Thanks
Marco

https://wordpress.org/plugins/woocommerce-predictive-search/