Can't read full page when viewing document, bottom 2-3 lines of page missing?

Just downloaded, installed and ID verified the Adobe Digital Edition file and successfully procured my first ebook.

After download and verification I can't read full page when opening and reading document, bottom 2-3 lines of page is missing? Have tried full screen view without luck. My plan was to use ADE because I many time can't wait for shipment of books, but have to go back to books if this problem can't be solved.

How to solve problem, please help???