Why do I get the message "this page is not editable"?

So you have installed Stastic on an existing website, or you created a new one, and now you are willing to edit a page or post, but Stastic does not let you do this and displays the message “this page is not editable” instead of an editable content?

Stastic page which is not editable

This happens in most cases because the page you are trying to edit has been generated by a Jekyll plugin, such as the jekyll-paginate plugin which splits your post list in several pages. Or the jekyll-sitemap plugin which creates a “dynamic” sitemap.xml file. Then the content you are trying to edit is simply not editable.