Check if your webpage is using the canonical link tag. The canonical link tag is used to nominate a primary page when you have several pages with duplicate or very similar content.
Check your URL:
How do I fix it ?
The Canonical Link Tag can be used when there are several pages with similar content and you want to tell the search engines which page you prefer to use in the search results. If your webpage does not have duplicate content and it has the preferred URL you must remove the canonical link tag.