HTTP status codes are three-digit numbers that inform crawlers whether a page is accessible, temporarily unavailable, or permanently moved. When a server returns an incorrect status code, the Yandex robot may stop indexing your content, leading to a drop in search visibility. Understanding these responses allows you to diagnose why pages disappear from results and how to align your site configuration with search engine requirements.
Why do status codes impact your search presence?
Crawlers rely on server responses to determine the status of a URL. If a server returns a 4xx or 5xx code, the search engine interprets this as a signal that the page should not be indexed or is currently broken. Even minor configuration errors on your hosting provider’s side can lead to the exclusion of important site sections.
Consider a scenario where a server misconfiguration causes a 503 error on a high-traffic category page. The crawler, seeing this signal, will pause its attempt to index that page. If the issue persists, the page is eventually dropped from the search index entirely. This happens because the crawler assumes the unavailability is intentional or a permanent failure.
Consistency is key. When your server provides reliable status codes, it builds trust with the crawler. Frequent, unexplained fluctuations in response codes can force the robot to reduce its crawl frequency, effectively slowing down the discovery of new or updated content on your site.
Common codes that cause indexing issues
- 200 OK: The standard success code indicating the page is ready for indexing.
- 301 Moved Permanently: Signals that the page has moved and authority should transfer to the new URL.
- 404 Not Found: The page does not exist, and it will be removed from the index.
- 500 Internal Server Error: The server failed to process the request, preventing the crawler from reading content.
- 503 Service Unavailable: Indicates a temporary overload or maintenance, signaling the robot to try again later.
How to diagnose server response errors
You should check server responses using the tools available in Yandex Webmaster. By selecting the server response tool, you can see exactly what the robot receives when it hits your URL. This confirms if your site is returning the status code you expect.
Beyond the basic check, you must look at your server logs. Logs reveal the full picture, showing which user agents are encountering which status codes and at what time of day. If you see a spike in 5xx errors during your peak traffic hours, it suggests your infrastructure is struggling to handle concurrent requests from both users and bots.
We often find that server-side caching mechanisms hide errors from site owners while feeding incorrect status codes to robots. Always test your headers directly from a server-level perspective rather than relying on browser inspection tools.
Alien Road SEO team
How Alien Road applies this
At Alien Road, we integrate status code monitoring into our standard site health audits. For a typical engagement, we first verify that the primary address is correctly configured to return a 200 code. We then audit all redirects to ensure that 301s point to the intended destination without creating chains.
We treat the identification of mirror sites as a priority. If a client has multiple versions of a site, we ensure only the primary address returns a 200 code. All other versions must redirect to the primary one. This prevents index dilution and ensures that link signals are consolidated where they provide the most benefit.
- Audit server logs to identify frequent 5xx errors during crawl sessions.
- Verify that your robots.txt file does not conflict with the server status.
- Check that mirror sites are not returning inconsistent status codes.
- Validate that temporary 302 redirects are replaced with 301s when the change is final.
- Confirm that primary site addresses are correctly identified within Yandex Webmaster.
What is the difference between 404 and 410 codes?
A 404 code signals that a resource is missing, which is standard for deleted pages. A 410 code explicitly tells the crawler that the page is gone and will not return. While both remove the page from the index, a 410 is a more definitive signal that can speed up the removal process for large sites.
If you are cleaning up thousands of legacy pages, using a 410 status code helps the crawler understand that it should stop attempting to re-crawl those URLs sooner than it would with a 404. This efficiency allows the bot to spend its time crawling active, high-value pages instead.
Do not fear the 404. It is a natural part of site lifecycle management. The goal is not to have zero 404s, but to ensure that genuine content is never mistakenly flagged as missing by your server.
Alien Road SEO team
How to resolve 5xx server errors
A 500-level error indicates that your server is struggling. This often happens due to database timeouts or memory limits during peak crawl activity. If you encounter these, check your server error logs and increase resource limits to ensure the robot can complete its crawl successfully.
It is also beneficial to verify if your firewall or security plugins are blocking the crawler. Sometimes, a security rule might misidentify a high-frequency crawl as a malicious attack, causing the server to return a 503 error. Adjusting these rules can resolve persistent indexing blocks without compromising your site security.
Where to start this week
Log into your Yandex Webmaster account and review the indexing report. Identify any URLs currently returning error status codes and categorize them by their response number. Fix the 5xx errors first as they indicate underlying server instability, then address 4xx errors by ensuring broken links are removed or redirected correctly.