Classification on Document Understading is not working with several pages

I have PDF’s files on which the page I require to extract the info is page 7 or sometimes further up to page 10.
When I try to go to “Classify Document Scope”, and use “Keyword Based Classifier” it can’t classify further than 1 page. (I think this because when I read the variable of “documentText” it is incomplete)

What can I do to still use “Keyword Based Classifier” and classify correctly my pdf’s files which keywords are up to page 7 and beyond?