What is the issue?
When pages do not contain a Twitter preview image, description, or title, it can result in your shared posts having an unattractive appearance and therefore might not drive as many engagements or clicks.
How to fix
Add Twitter cards to the header section of your website. There, you can add a title, description and image to improve how the page will be displayed on Twitter. This can usually be done directly in your CMS or via plugins. Learn more about this here.
Use number of sessions from Google Analytics to find which pages are more popular with your website visitors. These pages are more likely to be shared on Social Media channels, so you should prioritize these pages by adding Twitter card data to them first. Learn more in this article.