The Onpage module shows the results of how many landing pages are missing after we run our daily crawls. The daily crawl is done for the landing pages in your corresponding Google Analytics profile.
This is one way to observe any lost traffic because of the errors of missing landing pages.
To make this information noticeable, when the lost traffic overpasses 1% of the total monthly visits, in the SEO Campaign section of the app, you will see annotations on the graph that signal the issue.
If there is any problem with the crawling for the missing landing pages, there will be a Warning sign, on the designated column in the Dashboard section. This can happen if our bots are banned and in this kind of situation, an authorization will be necessary from your side.
Reach out to Customer Service in case you find yourself in this situation or if you have any other questions.