Websites serving error pages with an HTTP 200 status code risk deindexing and incorrect canonicalization by Google, leading to significant search engine optimization challenges.
This issue arises when server errors deliver content to Googlebot as a valid HTML page rather than indicating a problem, potentially causing Google to misinterpret the error content as legitimate page data or canonize it to a third-party URL.
One business and its supplier website recently experienced deindexing by Google, which subsequently canonized its pages to an online betting site, according to a discussion on Reddit.
Google Search Console’s live test validated the affected page, but a public rich results test displayed an “application error page,” indicating a discrepancy in how Googlebot and public tools perceive the content.
The problem often stems from temporary server errors that return an error message within a valid HTTP 200 response, rather than an appropriate server error status code.
John Mueller, a Google Search Advocate, has previously addressed similar issues, emphasizing the importance of correct HTTP status codes for search engine processing.
When a server returns an HTTP 200 status for an error page, Google treats it as normal content, which can lead to the deindexing of the intended page or its canonicalization to an unrelated, often third-party, URL.
To identify such issues, experts recommend examining HTTP access logs for variations in response size or indications of crawl failures.
A solution involves configuring the application to return an HTTP 503 (Service Unavailable) status code during server errors.
Returning an HTTP 503 status prevents Google from processing the error page as normal content, signaling to Googlebot that the issue is temporary and should not be indexed or canonized.
This approach helps maintain accurate indexing and prevents the unintended association of legitimate website content with error messages or external sites.
Source: Abondance
