AMP Page URL has canonical URL which is noindex
This means that the URL in question is an AMP Page URL, and contains a canonical tag pointing to a noindex URL.
Why is this important?
AMP HTML documents are required to have a canonical to the non-AMP equivalent (or a self-reference, if no equivalent exists). If this canonical is pointing to a URL that is noindex, search engines may not index the AMP URL.
The canonical tag is a mandatory element for AMP pages to be considered valid, and the canonical tag is supposed to point back at the original 'non-AMP' version of the page. If this page is noindex, this sends a conflicting signal to search engines - increasing the chances that the AMP page will not show up in search results.
What does the Hint check?
This Hint will trigger for any AMP Page URL which has a canonical tag pointing to a URL that is set to noindex.
Examples that trigger this Hint
Consider the AMP Page URL: https://example.com/amp/page-a/
The Hint would trigger for this URL if it included a canonical URL,
where this canonical URL had a noindex in either the <head> or the HTTP header (or both):
Meta noindex in the <head>,
OR in the HTTP header:
How do you resolve this issue?
The canonical on an AMP page should be pointing to a URL that is indexable.
To rectify the issue, you would need to fix the canonical on the AMP page so that it points back to the (correct) non-AMP version of the page, and ensure that this page does not contain a noindex tag.
You would also need to ensure that the non-AMP version of the page has a self-referencing canonical. It should look like this:
For the URL: https://example.com/pages/page-a/
This page defines a self-reference canonical and an AMP page:
Then the AMP page has a canonical pointing back at https://example.com/pages/page-a/