Critical Technical SEO
Client error (4xx)
- Severity
- Critical
- Impact
- High
- Effort to fix
- Low
- Issue code
http_4xx
Why it matters
The URL returns an error such as 404 Not Found. Visitors and crawlers reach a dead end and link equity is lost.
How to fix it
Restore the page, 301 redirect it to the most relevant live URL, or remove the links that point to it.
Common causes
- A page was deleted or its URL changed without a 301 redirect, for example after a site migration, a CMS slug edit or a discontinued product.
- A typo in a hard-coded link in navigation, a footer or a blog post.
- Relative links that resolve to the wrong folder, such as
href="page"instead ofhref="/page". - A 410 Gone that is intended for removed content. That is fine if nothing links to it any more.
Choose the right fix
| Situation | Fix |
|---|---|
| The page moved | 301 redirect the old URL to the new one, then update internal links to point straight at it |
| A close replacement exists | 301 redirect to the closest equivalent, not to the home page |
| The content is gone for good | Remove or update the links pointing to it; a 404 or 410 is then correct |
| The page has backlinks | Always redirect. Import backlinks to find these; see Broken page with backlinks |
Use Inlinks in the URL details to find every page that links to the broken URL. Fixing the links matters as much as fixing the page.
How it affects your score
Finding this issue on any page costs the Technical SEO score 8 points, plus up to 25 more depending on the share of crawled pages affected. As a critical issue type it also takes 3 points off overall site health (critical deductions stop at 15 points). Blocks indexing, breaks pages or loses traffic. Fix these first.
Find the affected URLs
Open Crawl > Issues and pick Client error (4xx). Each affected URL is listed with its evidence, and Copy URLs or Export URLs hands the list to a developer. The issue also appears in the Action Plan, ranked by impact (high) and effort (low), and in the issues CSV under the code http_4xx. After fixing, run a new audit and use Compare to confirm the URLs moved to fixed.