Insert a table of contents

The manuscript needs a table of contents showing Heading 1 and Heading 2 entries with correct page numbers. Insert the table of contents at the start of chapter one, use dot leaders, and ensure page numbers match the current pagination.

Before the editors see this, make the table of contents scannable. Show only Heading 1 and Heading 2, collapse long titles after 50 characters with ellipses, use dot leaders to page numbers, and mark any headings that are missing correct styles so a reviewer can approve quickly.

I inserted the table of contents, but several chapter titles are missing from it because they appear as plain text instead of Heading 1. The managing editor will complain. I am not sure which sections were hand-styled. What's the most likely reason headings didn't appear, and what step-by-step fix will get the TOC accurate before the deadline?

Each time authors tweak wording or paste content, the TOC breaks and I spend time hunting for misapplied styles. Over the last six books this costs me hours. Where does this pattern come from, and what practical rules or a small author checklist will stop TOC errors and keep my book ready for print?