Docx file not getting converted to epub with table of contents

I am trying to convert an msword docx file to an epub.

The word file has auto-generated headings section. So I want those headings to read as table of contents.

However, only 4 headings are coming out in the clickable table of contents that shows up on the left in the calibre reader, as well as in the Kindle viewer.

What should I do?

Here's what the word file looks like with the headings.
https://i.imgur.com/M4ML1fz.png

Here's how the headings are coming out in the table of contents of the resultant epub file.
https://i.imgur.com/UJruyoS.png

I didn't do any specific settings in the docx file.

I am enclosing both the source docx file and resultant epub file.

Attached Files

	Naval BlogsCompilation - Naval Ravikant.epub (531.0 KB)
	Naval_Compilation.docx (257.8 KB)