The page must be divided into logical sections using headings. H1-H6 can be used.
How to resolve this issue
Most pages created through the Drupal CMS platform should have a pre-assigned heading according to the page title.
If the error occurs on a page that wasn’t created through the Drupal CMS platform, please insure that the main page title has assigned an H1 heading <h1>This is a heading</h1>
If the page was created through the Drupal CMS platform, please edit the content of that page by logging in to the CMS platform, selecting the page with the error, then assigning (Heading 1) to the page title using the format tab. Usually this error occurs on panel pages.