What can be reason for pages not being indexed given they are already indexed earlier

There are several reasons why pages that were previously indexed by search engines like Google or Bing might become unindexed or removed from the index, even though they were indexed earlier. If a page was indexed and later disappears from search results, it could be due to various technical, content-related, or algorithmic factors. Below are the most common reasons why this might happen:

1. Technical Issues

• Noindex Meta Tag or HTTP Header: One of the most common reasons for a previously indexed page to become unindexed is the accidental addition of a noindex meta tag or an HTTP header that tells search engines not to index the page. If a page previously had a noindex tag added, search engines would re-crawl the page and remove it from the index.
  • Solution: Check the page’s source code or headers to ensure the noindex directive is not present.
• Blocked by Robots.txt: If the robots.txt file is configured to disallow crawlers from accessing the page, search engines will be unable to index it. Sometimes, website owners inadvertently block crawlers from important pages using the robots.txt file.
  • Solution: Check the robots.txt file to ensure the page is not blocked from being crawled by search engine bots.
• Crawl Errors: Pages may be removed from the index if Google or Bing encounters repeated errors while crawling them. These errors could include 404 errors (page not found), 500 server errors (internal server issues), or other issues that prevent proper crawling.
  • Solution: Use tools like Google Search Console or Bing Webmaster Tools to check for crawl errors and resolve any issues. Fix any broken links or server errors that might be preventing proper crawling.

2. Content Issues

• Duplicate Content: Search engines may remove pages from their index if they find the content to be a duplicate of other pages on your site or elsewhere on the web. Google, in particular, strives to present the most relevant content, and duplicate content can be seen as spammy or low-quality.
  • Solution: Check for duplicate content using tools like Copyscape or Siteliner. If duplicates are found, consider using canonical tags to indicate the preferred version of the page or updating the content to make it unique.
• Thin or Low-Quality Content: Pages with very little content or content that does not provide value to users can be deindexed. If Google or Bing deems that a page doesn’t meet quality standards (such as having insufficient text, no meaningful information, or being overly focused on ads), they may choose to remove it from their index.
  • Solution: Enhance the content by providing more valuable information, improving the readability, and making it more comprehensive and useful for users.

3. Algorithmic or Manual Penalties

• Algorithmic Penalties: Search engines continuously update their algorithms. If your page was initially indexed, but later removed, it might have been penalized due to a change in the search engine’s ranking algorithms. For instance, Google’s Panda or Penguin updates focus on penalizing low-quality content, keyword stuffing, or link schemes. If the page violates any of these guidelines, it might get removed from the index.
  • Solution: Review your content and backlink strategy to ensure you’re adhering to Google’s Webmaster Guidelines and best practices. If necessary, make improvements and submit a reconsideration request if the issue is severe.
• Manual Penalty: In rare cases, Google may issue a manual penalty for violating guidelines. This could involve spammy behavior, such as unnatural link building or cloaking, which can result in pages being removed from the index.
  • Solution: Check Google Search Console for any manual action notifications. If a penalty has been imposed, follow the instructions to resolve the issue and submit a reconsideration request.

4. Content Removal or Page Changes

• Page Deletion: If the page was deleted or moved without proper redirection (such as a 301 redirect), search engines may eventually remove the page from their index. Even if a page was indexed earlier, if it no longer exists or was moved to a new URL without proper redirection, the search engines will drop it from the index.
  • Solution: If a page was moved, set up proper 301 redirects to the new URL to ensure both users and search engines are directed to the correct page. If the page was deleted but you want it indexed, restore the content or provide a redirect to a related page.
• URL Parameters or Session IDs: Some sites use dynamic URLs with session IDs or tracking parameters that can cause issues with indexing. If these pages are frequently generated with different parameters, search engines might see them as separate pages or duplicate content, leading to indexing problems.
  • Solution: Ensure that URL parameters are set up correctly in Google Search Console to avoid unnecessary duplication. Alternatively, implement canonical tags to indicate the preferred version of the page.

5. Poor Internal Linking Structure

• Lack of Internal Links: Search engines rely on internal linking to discover new pages and crawl the website more effectively. If a page is not well-linked internally or does not have external backlinks pointing to it, search engines may fail to find the page during their crawling process, which can lead to it being deindexed.
  • Solution: Ensure that important pages are properly linked from other pages within your site. You can also build external backlinks to these pages to increase their authority and visibility.

6. Search Engine Algorithms and Indexing Delays

• Indexing Delays: Sometimes, there may simply be a delay in search engines updating their index. If a page was indexed but is no longer appearing in the search results, it could be due to a delay in the algorithm or indexing refresh cycle.
  • Solution: Be patient and allow time for the search engines to re-crawl the page. If it remains missing after some time, investigate the other potential issues listed above.
• Search Engine Algorithm Updates: Search engines periodically update their algorithms, and during these updates, some pages might experience fluctuations in their rankings or indexing status. A page that was once indexed might get removed temporarily or permanently as search engines adjust their ranking and indexing algorithms.
  • Solution: Keep an eye on algorithm updates and adjust your site’s content and structure to comply with the latest best practices. Tools like Google’s Search Central Blog can help keep you informed.

7. Sitemap Issues

• Outdated or Missing Sitemap: If your sitemap is outdated, incomplete, or not properly submitted to Google or Bing, search engines may not be able to find or index certain pages on your site. If the page is not listed in your sitemap, it may not get crawled and indexed regularly.
  • Solution: Ensure your sitemap is up-to-date and submitted to both Google Search Console and Bing Webmaster Tools. Regularly check that all important pages are included in the sitemap.

Conclusion

There are several reasons why a previously indexed page might be deindexed by search engines, ranging from technical issues, content problems, penalties, or even natural changes in algorithmic ranking criteria. To troubleshoot, start by checking for technical issues such as noindex tags, crawl errors, or robots.txt settings. Also, examine the quality and uniqueness of your content, and make sure that the page hasn’t been penalized or removed due to algorithmic changes. By using tools like Google Search Console, Bing Webmaster Tools, and regularly auditing your website, you can identify and resolve indexing issues and ensure that your pages remain visible in search engine results.