First check, if all the page texts are found. One common thing is, that page has so called embedded code, which includes iFrame. iFrame content is not included for translation project.
Sometimes too "complex" page structure may cause problems. Use more text elements to separate paragraphs and make page layout simpler. In practice, this means that if a sentence is "My name is Jack " In this sentence "name" is bold and it's in the middle of the sentence. Because it's bold (different formation) it's a separate string. Therefore, you see three (3) different strings ("My" "name" "is Jack") on our translation view instead of one "My name is Jack". This applies to any other formations between sentences etc. It's important to keep styling in mind when doing the website as it affects localization.