Google found a page title duplicated when it matches exactly same as other page URL. Adding page ids to each of the paginated pages could resolve this issue. For example, if your page is www.example.com/xyz is the original paginated page. Then you can create each one as www.example.com/xyz?as2345as_page=1 www.example.com/xyz?as2345as_page=2

What is the optimum number of keywords to be targeted for SEO? What are the factors to be considered while choosing keywords?