This error occurs when the page has a canonical to a different page. For example
The page URL is https://www.mysite.com/en/uk/somepage.html but the canonical tag on the page references a different URL. In this case it is pointing to the http version. These are two different pages and they must match.
<link rel=”canonical” href=”http://www.mysite.com/en/uk/somepage.html”/>
Common reasons for mismatched canonicals.
- Canonical To HTTP or HTTPS version
- Canonical to Trailing Slash
- Canonical to Parameter
Real example:
In the example below, Chase Bank has a page for Spanish speakers https://www.chase.com/espanol and they have set a hreflang to pair it with the main English home page. When you go to the /espanol page the canonical on that page tells the search engines to ignore the /espanol page and take the global page. This will create an error and will result in a return tag error for the Spanish version of the page since the search engine will ignore that URL.
