SiteAud!tLint Support

Critical Technical SEO

Server error (5xx)

Severity
Critical
Impact
High
Effort to fix
Medium
Issue code
http_5xx

Why it matters

The server failed while generating the page. Repeated 5xx responses can cause pages to drop out of the index.

How to fix it

Check server and application logs for this URL and fix the underlying error.

What this means

The URL returned a server error: 500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable, 504 Gateway Timeout or similar. The evidence shows the exact status.

Why it matters

A 5xx tells crawlers the server failed. Google retries for a while, but pages that keep returning 5xx are crawled less often and eventually dropped from the index. Sitewide 5xx errors also make Google slow its crawl of the whole site.

How to tell a real problem from a crawl problem

  • Many pages, during the crawl only: the server may be struggling with the crawl rate. Lower Parallel requests and raise Delay between requests in Crawl settings, then recrawl. If the errors go away, the server is fragile under load, which also affects Googlebot and busy traffic periods.
  • The same few URLs every time: a bug in those pages, such as a failing database query, a missing template variable or an exception in a plugin.
  • 503 everywhere: a maintenance mode or an overloaded host.
  • 502 or 504: the web server or CDN could not get an answer from the application behind it in time.

How to fix it

  1. Open the URL in a browser. If it fails there too, check the server's error log at the time of the request; it names the exact cause.
  2. For pages that fail consistently, fix the code or data that triggers the error.
  3. For load-related errors, add caching, raise hosting resources, or tune the application server.
  4. During planned maintenance, return 503 with a Retry-After header. Google treats that as temporary.

Verify the fix

Recrawl with the same crawl settings and compare. Errors that move to 200 are fixed; ones that come and go point to capacity rather than code.

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 Server error (5xx). 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 (medium), and in the issues CSV under the code http_5xx. After fixing, run a new audit and use Compare to confirm the URLs moved to fixed.