This rule determines if the page has a defined canonical URL by checking for
<link rel="canonical" href="Canonical page URL here">.
A canonical URL is the URL of the page on your site that Search Engine (Bing, Google, and the like) believes is the most representative of a group of duplicate pages. For instance, if you have two URLs for the same page (
example.com/productId/5), the Search Engine will select one as canonical.
Search Engines consider duplicate copies of the same page to be a single page accessible via various URLs or distinct sites with similar content (for example, a page having both a mobile and a desktop version). Search Engine will select one URL as the canonical version and crawl it, while all other URLs will be treated as duplicates and crawled less frequently.
If you do not explicitly inform the Search Engine which URL is canonical, the Search Engine may make the decision for you or may consider them both to be of equal weight, which may result in undesirable behavior.
How to fix it
- Make sure the
<link rel="canonical" href="Canonical page URL here">is defined and point to a canonical URL.
- Ensure that canonical points to the right page and that it does exist.
- Specified canonical should be crawlable and indexable. Sometimes page might be crawled, but not indexed. In Google Search Console it is reported as
Crawled – currently not indexed.
SiteLint, SEO, Best Practice