There is no Content section on the template of this page. Make sure the page template is correct.

You may see this warning at the top of your page right after launching Visual Builder:

Usually this warning means that page template of the post type (page, post, custom one) that you are trying to edit does not have content area. Sometimes theme developers create page layouts that can be edited using widgets or other custom solutions. In this case you should switch to another page template to use Visual Builder or follow recommendations of your theme provider in regards to this page template.