Hi Gustavo, First of all I want to tell you about the duplicate content. Duplicate content always hurt your website ranking & which overall decreases the website visibility.This duplicate content is easily recognized by google which results in removing the webpages from indexing.The first thing you need to do is to identifying the duplicate content on your website & If you find the duplicate content then it should be fixed by using several fixing techniques for duplicate content that was mentioned in the below :
Fixing the the duplicate content
I think that above link helps you to solves the problem of duplicate content.