Check the navigation. Is it as full as you want? Are the lists and sublists nested properly? There is a good chance that the nesting went sideways. There is also a good chance that the page numbers need to be edited out of the titles that got pulled through into the navigation. In our small sample ebook the TOC.xhtml looks like this.
The numbers 3, 5, and 19 in front of the nav items need to be deleted. Those are from the page stakes.
Other things that need to be done:
Add a language declaration to the root HTML element
Add the CSS
Line 7 needs DPUB ARIA (pagelist does not have a corresponding ARIA role)
Consider making those lists blank list items
Edit the <title> field
Be cautious about more complex contents lists that are meant to nest. This frequently goes sideways out of InDesign (nesting HTML properly is not an InDesign competency). In the case of this book, the TOC style was built properly, asking the TOC to nest the chapter numbers under the part titles.
But this is the TOC fresh out of InDesign, which you can see it not nesting the chapters as sublists under the part titles.
This TOC is cleaned-up, with the sublists nested in <ol>s.
