What does this mean?
The title tag is considered important to help both users and search engines quickly understand what content can be expected to find on the page.
The title tag is considered one of the most important on-page SEO factors, so if it is missing this represents an issue that may affect search engine rankings and click-through-rate from the search results.
What to do?
You can automatically fix this issue for WordPress websites, by clicking on the "Autofix" button. Try adding some to improve SEO performance.