Tutorial objective
This tutorial helps you act on the Detectable 404 Page result. It explains what the signal means and how to review it without breaking the underlying HTML, headers or JSON structure.
Learn how to check whether a nonexistent URL correctly communicates its status and prevents bots from interpreting errors as valid content.
What AISEO reviews in Detectable 404 Page
AISEO reviews whether HTTP 404 is present, coherent and technically useful within the Crawling area.
Presence
The signal exists in the expected place.
Technical output
The real HTML, headers or JSON output matches the intended configuration.
Coherence
The signal does not contradict links, canonical URLs, sitemap entries, headings or other related signals.
AI readability
The page becomes easier to interpret, extract and reuse by automated systems.
How to interpret the result
Pass
The signal is present, coherent and aligned with the page purpose.
Warning
The signal exists, but it may be weak, generic, incomplete or partially inconsistent.
Fail
The signal is missing, contradictory or technically harmful for crawling, interpretation or trust.
Basic manual review
- Inspect the source code, server response or generated markup related to HTTP 404.
- Check the final browser and crawler-visible output, not only the visual interface.
- Compare the signal with the page purpose, content and internal architecture.
- Repeat the check after applying changes in templates, CMS, plugins or server configuration.
Common errors
- Assuming Detectable 404 Page is correct because the page looks fine visually.
- Leaving old configuration after a migration or redesign.
- Mixing several signals that point in different directions.
- Fixing only one page while the same template keeps generating the issue elsewhere.
How to fix it
- Define what the correct HTTP 404 signal should be for the URL.
- Apply the change at the source: template, CMS, server, component or data layer.
- Keep the HTML, JSON and structured code valid after the edit.
- Run the AISEO check again and confirm that related signals still remain coherent.