Page title not defined — what does it mean?
Sometimes, you may see
Page title not defined among page titles in the page title report. It happens when the title of your page is not set. It’s highly recommended to define all page titles because they matter to search engines and help your website to rank higher in search results. Also, with page titles, you can read and understand analytics reports better.
If you miss some page titles, set them up in your WordPress or other content management system.