The situation emerges when a URL is marked with a canonical tag that points to a noindex URL (for instance, if Page A canonicalizes to Page B, whereas Page B is marked as noindex).
Why is this important?
Canonical tags are meant to clearly designate a primary URL for search engines to index. Yet, when the canonical points to a noindex URL, it gives search engines mixed signals; Page A directs to index Page B, but Page B instructs not to be indexed.
This often leads search engines to disregard the canonical links and decide on their own which URL should be canonical. This confusion could cause the indexing of incorrect URLs, engendering issues with redundant content.
What does the Optimization check?
The Optimization activates for any internal URL that contains a canonical tag linking to a noindex URL as its chosen canonical reference.
Examples that trigger this Optimization:
Imagine the URL: https://loudinteractive.com/page-a
This URL would activate the Optimization if it had a canonical tag pointing to a different internal page, shown below:
<link rel="canonical" href="https://loudinteractive.com/page-b" />
And if the URL indicated in the canonical tag https://loudinteractive.com/page-b had a noindex directive:
<!doctype html><html lang="en"><head> <title>Example Title</title> <meta name="robots" content="noindex" /> ...</head><body> ... </body></html>
How do you resolve this issue?
To rectify a misconfigured canonical setup, determine whether Page B is the correct canonical for Page A. If so, the noindex directive should be removed from Page B. If Page B is correctly marked as noindex, then you should alter Page A’s canonical tag to either refer back to Page A itself or to point at a different, indexable URL.
Resolving these issues will often require a tailored approach for each individual case.