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Response codes

Each request to a website has it's own response code. Explanations can be found on serveral locations like on, wikipedia or http cats.

HTTP 418 I'm a Teapot
HTTP - 418 I'm a Teapot.
  • 2XX : Ok
  • 3XX : Redirect
  • 4XX: Not found or not accessible
  • 5XX: Server error

Working pages will report a 200 or 206.

After the existing official response codes, the component uses some custom values.

In the 5XX range, there are custom codes used by cloudflare:

  • web server returns an unknown error (520)
  • web server is down (521)
  • connection timed out (522)
  • origin is unreachable (523)
  • a timeout occurred (524)
  • SSL handshake failed (525)
  • invalid SSL certificate (526)
  • other (530)

Custom codes

WAF (Cloudflare)

This is a custom variation on a 403 Forbidden error when caused by a Firewall (currently only Cloudflare is detected and reported).

DNS Failure

The hostname in the request didn't resolve to an IP address to send the request to. On some servers a DNS failure will loop back to the servers name and IP.

Ignored by setting

The links should not be checked based on either 'Domains to ignore' or 'Paths to ignore' in the components configuration.

Unchecked protocol

Links with protocols  like mailto: and ftp: that can not be checked. You can completely ignore these links with the 'Unkown protocols' setting in the components' configuration.

Too many redirects

Too many hops to reach the destination, mostly caused by some kind of (cookie) firewall or server misconfiguration.  You can set the number of hops using the 'Follow Redirects' and 'Max Redirects' settings in the components' configuration.

SSL Certificate Error & SSL Version Handshake Error

Failed SSL connection can have multiple causes.

The most common ones are:

  • The certificate is expired.
  • The certificate does not match the reached host. This occurs for example if the hosting expired and the site is pointing to a generic 'catch all' domain.
  • The certificate was signed by an unknown certificate authority. If the page works fine in your web browser, probably the certificate chain is not configured properly. Most browsers will fix this issue by downloading the missing intermediate certificate()s. The checker can not do this and therefor it can not verify the signature of the intermediate on your websites certificate. If this problem occurs on your own site, have the certificate chain fixed to ensure combinability with all browsers.
Simple SSL Certificate Chain
Simple representation of a Certificate chain. For a more detailed example see the Lets encrypt Chain of Thrust

Redirect Ignored

The link redirects, but this redirect is configured to be ignored with the 'Domains to ignore redirects' option.

Unable to check

What is heck is going on?

Provider lookup Failed

Fetching the embed code using the oEmbed/Facebook provider plugin failed

Unknown Error

What is heck is going on (too)? Unhandled error from curl.

Request rate throttle

Checking this link is skipped based on the 'Domain throttle' settings in the components' configuration.


The request took longer than the configured 'Request Timeout' in the components' configuration. If the remote server itself reports a timeout, it should be a Request Timeout (408)