What is the issue?
The sitemap.xml gives search engines an overview of your website structure, and shows them which pages on your website should be indexed. Only indexable pages should therefore be included in your sitemap. Including non-indexable pages wastes search engine resources that could be saved for more important pages.
How to fix
Remove non-indexable pages from the sitemap, and resubmit the sitemap to Google Search Console. The column "document" in the report below shows you the web page that is not indexable, including the reason. The next column shows you in which sitemap the reference is contained, as bigger websites often have more than one sitemap. You can download the list and pass it directly to your developer or technical team so they can remove the page from the sitemap. Learn more about this in our wiki and product insights.
Use the number of sessions from Google Analytics to find relevant, indexable pages that should be included in the sitemap. Adding these URLs to the sitemap will make it more likely that they rank highly in Google. Learn more in this article.