Next/Prev Paginated URL is canonicalized to different URL
This means that the URL in question is a pagination URL using rel="next" and rel="prev" link elements, yet is also canonicalized to a different URL.
Why is this important?
Rel="next" and rel="prev" link elements are added to pages to indicate that they are part of paginated series. Canonicalizing a URL, however, indicates that it is duplicate content, and the canonical URL should be considered preferential.
This results in a mismatch of two different concepts, and can be very damaging. A typical example of this is when paginated pages all point to 'page 1' of a series as the canonical. This is one of the most common mistakes noticed by Google regarding the use of canonicals.
In their words:
"Specifying a rel=canonical from page 2 (or any later page) to page 1 is not correct use of rel=canonical, as these are not duplicate pages. Using rel=canonical in this instance would result in the content on pages 2 and beyond not being indexed at all."
What does the Hint check?
This Hint will trigger for any internal URL which uses next/prev elements, and is also canonicalized to a different URL.
Examples that trigger this Hint:
Consider the paginated URL: https://example.com/page-a?p=5
The Hint would trigger for this URL if it contained both rel=next/prev and a canonical tag in the <head>:
The above example shows link tags defined in the HTML, but this would also trigger if they were defined using HTTP headers (or some combination of the two methods).
How do you resolve this issue?
This is a scenario where the pagination markup is set up correctly, but the presence of the canonical is causing issues. A solution might be as straightforward as removing the canonical tags, or making them self-referential. However, a range of options exist for implementing pagination markup, which are laid out on Google's article here.