What is the issue?
Unique page titles help you to stand out in Search Engine Result Pages (SERPs) and improve your click-through-rate (CTR) by providing an enticing and accurate description of your page's purpose. Page titles also pass on ranking signals to Search Engines, so should therefore contain the focus topic in a clear way. Duplicate page titles are problematic as they can be a sign of spamminess or duplicate content.
How to fix
To fix this issue, ensure that each page has a descriptive and unique page title which can be specified in your CMS. Use Search Success to measure your page's CTR, so that you can test which meta titles drive increased traffic. Learn more about this here.
Unoptimized and duplicate meta titles can result in less clicks and sessions to your website. Use Google Analytics data to find pages with duplicate page titles that receive a high number of sessions, and fix these pages first. Learn more in this article.