Every page is built on top of a template. Almost all templates have a Main or Content section, to put your main content in. These “sections” are called placeholders. Next to that, you can have placeholder for Header, Footer, Menu etc.
On your page, you are using a template which doesn't have the “Cancel” placeholder anymore. Make sure you use the Structure Mode, so it will show a red bar indicating the non-existing placeholder. Move everything from that placeholder to another placeholder to resolve the problem.
Good luck!