Cant edit Word app .doc headers/footers space

I use the word app on a mobile device called Boox. I have a large .doc and the first 35 pages are fine. Margins are standard. Page 36 onward, despite selecting standard margins, shows serious gappage. I think header/footers pg 36 forward are off but cant change them. When I click on the header footer area anywhere of the first 35 Pages they're called header/footer section 1. Page 36 onwards for hundreds of pages it says header/footer section 2. I can't edit the size and I can't remove header or footer and it's taking up four inches of page ahead of the margins setting. Im stuck!