The h1 tag is not written in the article

If you encounter such a problem, first check Is the “Remove h1 tag” checkbox in the “Publishing” tab unchecked?

If it is removed, it means that the AI did not generate the h1 tag. This often happens, for example, when writing articles according to a plan. But don't worry about this: many CMS (including WordPress) automatically add an h1 tag to the page, which is equal to the title of the article. In this case, you don’t need the h1 tag in the body of the article, because it shouldn’t be duplicated in the article.