footer appears in middle of content not at the bottom of the screen

The footer is appearing in the middle of the screen on my pc and on my tablet, but OK on the phone. This is only on two pages. Page URL’s are https://www.my-familytree.net/our-tree/ and https://www.my-familytree.net/family-tree-2/
Doesn’t seem to matter what browser you use, this still happens.
If this can’t be fixed, how to remove the footer altogether?

The page I need help with: [log in to see the link]