Need Help on Technical Documentation Project

Hello guys, I need help with my project, currently stuck at 15/16 passing the test suite.
I think my pen didn’t pass the User Story #14 but the navbar is already fixed on left side.
Here is the link to my pen:
https://codepen.io/batpoop/full/dypExEY

4. Each element with the class of "main-section" should also have an id comprised of the innerText contained within it, with underscores in place of spaces. The id may include special characters if there are special characters in the respective innerText. (e.g. The that contains the header, "JavaScript & Java", should have a corresponding id="JavaScript_&_Java"). Some "main-section" elements are missing the following ids (don't forget to replace spaces with underscores!)

This is the error you are getting. Your main sections should also have an id with same name as header of that section.

Apparently, I was missing an underscore on one of the headers.
Thank you for your help.