QB Tech Documentation Page Review

Hey, everyone, I am trying to understand what is wrong here where when I analyze it, it says that there are no errors, however, when I run the test I get 15/16??
Technical Documentation Page Review Please

@dominionworkz, when a test fails click the red button to see which test(s) are failing and text to help you correct the issue.
Be sure and read more than just the first line of the failing message. The ability to read and comprehend error messages is a skill you’ll need to acquire as a developer. Ask questions on what you don’t understand.

The full failing test message says

Each <section> element with the class of "main-section" should also have an id comprised of the <header> innerText contained within it, with underscores in place of spaces. The id may include special characters if there are special characters in the respective <header> innerText. (e.g. The <section> 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!) : INTRDUCTION : expected 1 to equal 0
AssertionError: Some "main-section" elements are missing the following ids (don't forget to replace spaces with underscores!) : INTRDUCTION : expected 1 to equal 0

Do you understand what the test is looking for and why it fails?

On a side note, you shouldn’t copy the sample code or try and replicate the projects. They show one way the project can be completed.
The instructions say to make yours “functionally similar” and to “give it your own personal style”.

Thank you for the feedback & will consider your input