The AMP Page URL in question includes a canonical link element that points to a URL returning an Error (5XX).
Why is this important?
It's essential for AMP HTML pages to reference a canonical page, either towards a non-AMP version or itself if there's no alternative. A canonical directed to a 5XX Error URL prevents search engines from reaching the original page, undermining the validity and discoverability of AMP pages, and sending search engines confusing signals, which can negatively affect the appearance of the AMP page in search results.
What does the Optimization check?
This check will be flagged if an AMP URL's canonical tag points to a URL that yields an Error (5XX) when accessed.
Examples that trigger this Optimization
Take the AMP URL: https://loudinteractive.com/amp/page-1/
This check would be activated if the AMP URL contains a canonical link to:
<!doctype html><html amp> <head> <meta charset="utf-8"> <title>Example Document</title> <link rel="canonical" href="https://loudinteractive.com/pages/page-1/" /> ... </head> ...</html>
and the referenced canonical URL provides a 500 (Internal Server Error) response:
HTTP/... 500 Internal Server Error...
URLs triggering other server error statuses will also activate this Optimization, thus any 5XX series response is included.
How do you resolve this issue?
Marked as 'Critical', this issue can significantly hinder site traffic from organic searches and needs urgent attention. If the problem is the server, you'll have to diagnose server issues potentially with a developer or server admin to identify and resolve the root cause. If the canonical link is incorrect, correct the AMP page's canonical to point to the right non-AMP version, which itself should correctly point back as self-referential.
Consider a non-AMP URL like https://loudinteractive.com/pages/page-1/ that defines both self-reference canonical and an AMP page link as follows:
The corresponding AMP page should then have a canonical pointing back to https://loudinteractive.com/pages/page-1/
<link rel="canonical" href="https://loudinteractive.com/pages/page-1/" />