TOC not nesting properly when publishing to HTML5

[s2767656clue]

When publishing my book to HTML5, the first 3 chapters of the book publish correctly in the left pane in HTML 5 generated output.  However, the remaining chapters all populate nested under the 3rd chapter (see below). How do I solve this? 

• Chapter 1
  • Sub section
• Chapter 2
• Chapter 3
  • Sub section
    • Chapter 4
      • Sub section
        • Chapter 5

[Matt-Tech Comm Tools]

Can you post a screenshot of your book file?

Is the paragraph style applied to Chapter 4 the same as for Chapters 1-3?

[s2767656clue]

Unfortunately, I am unable to post a screen shot. 

However the paragraph style is applied to all chapters the same. 

[Matt-Tech Comm Tools]

Are you using groups or folders in your book?

Is the TOC for the book a different icon than the others? (Is the TOC a generated file?)

[s2767656clue]

I am using groups in my book.

Yes, the TOC is a generated file. 

[Matt-Tech Comm Tools · Accepted solution]

So does the group structure correspond to the inconsistencies in the TOC in the HTML5?

If yes, remove the group structure to see if it remedies the problem.

Groups can have special settings like templates and numbering, so you can also check those control mechanisms if you're not able to simplify the structure of the book.

[Matt-Tech Comm Tools]

Sounds like you got it remedied!!

Was it the group structure, or the settings within the group that fixed the problem?

[s2767656clue]

It was the group structure that was the problem. Thank you again