Cause: #
A page title is often treated as the most important on-page element. It is a strong relevancy signal for search engines because it tells them what the page is really about.
It is of course important that the title includes your most important keyword. But more to that, every page should have a unique title to ensure that search engines have no trouble in determining which of the website pages is relevant for this or that query.
Pages with duplicate titles have fewer chances to rank high. Even more, if your site has pages with duplicate titles, other pages may be hard to get ranked as well.
You should avoid duplicate page titles (meta titles) on your website because the more duplicate content and duplicate page titles (meta titles) you have on your website, the worse those pages will rank in the search engine’s page rank.
How to resolve it: #
Check which page has a duplicate title issue and try to rewrite it as per page content or keyword.