Subpage duplication
Every single page must have its unique title, description and content. Check your website thoroughly. If you have two pages with the same content, title and description: delete one of the pages because the searchbots will think that you want to mislead them. If the content is diferrent, but similar, change the meta elements. Modify the contents to make them more different. If the two pages are similar on purpose (two products are the same except for the color), it is advised to merge them somehow.