Preventing Duplicate URLs
- A page and a post should never share the same title.
- If you use the Duplicate Post plugin, always change the title and the URL of the Clone page to something unique.
- Only publish pages that you plan to use.
- Delete unused pages and drafts.
For More Information Please Refer: https://www.wpfixit.com/wordpress-duplicate-content-issues-and-how-to-fix-them/