Error map
308 HTTP 308 Permanent Redirect
HTTP · layer 2, Network
Centre: this error. First ring: errors it is linked with (11). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (11)
HTTP 302 Found (Temporary Redirect)
The resource is temporarily at another URL; clients should keep using the original URL for future requests.
HTTP 100 Continue
An interim response telling the client to go ahead and send the request body — normal when the client sent Expect: 100-continue.
ERR_TOO_MANY_REDIRECTS with Cloudflare (Flexible SSL redirect loop)
The page redirects to itself forever — classic cause: Cloudflare SSL mode “Flexible” while the origin redirects HTTP to HTTPS.
HTTP 103 Early Hints
An interim response that sends Link headers early so the browser can preload CSS, fonts or scripts while the server is still buil…
HTTP 410 Gone
The resource used to exist but was intentionally and permanently removed, with no forwarding address.
HTTP 303 See Other
A redirect telling the client to fetch the result from another URL with GET — used after a form POST so refreshing doesn’t resubm…
HTTP 307 Temporary Redirect
A temporary redirect that keeps the original method and body — a POST stays a POST at the new URL.
WordPress: ERR_TOO_MANY_REDIRECTS / redirected you too many times on wp-admin or the whole site
WordPress and the server/proxy keep redirecting to each other — usually siteurl/home mismatch (http vs https, www vs non-www) or…
HTTP 301 Moved Permanently
The resource has a new permanent URL; clients and search engines should use the address in the Location header from now on.
Chrome: This page isn’t working — example.com redirected you too many times. ERR_TOO_MANY_REDIRECTS
The page keeps redirecting to itself or in a loop, so the browser gives up after about 20 redirects.
Firefox: The page isn’t redirecting properly — Firefox has detected that the server is redirecting the request in a way that will never complete
Firefox's wording for a redirect loop (Chrome calls it ERR_TOO_MANY_REDIRECTS).
Two steps away (30)
HTTP 401 Unauthorized
The request has no valid authentication credentials — you need to log in or send a valid token.
SyntaxError: Unexpected token < in JSON at position 0
`JSON.parse()` / `response.json()` received something that isn’t JSON — very often an HTML error page.
HTTP 200 OK (but something is still wrong)
The request succeeded at the HTTP level — yet the page is blank, the data is wrong, or an error is hidden inside the response bod…
HTTP 413 Content Too Large (Request Entity Too Large)
The request body is bigger than the server is willing to accept — usually a file upload over the configured limit.
Warning: Cannot modify header information - headers already sent
You called `header()`, `setcookie()` or `session_start()` after output had already been sent to the browser.
CORS Error: No 'Access-Control-Allow-Origin' header is present
The browser blocked a cross-origin request because the server’s response didn’t include the CORS headers allowing your site’s ori…
Cloudflare Error 525: SSL Handshake Failed
Cloudflare couldn’t complete a TLS handshake with your origin (SSL mode Full / Full strict).
ERR_SSL_VERSION_OR_CIPHER_MISMATCH on a Cloudflare site (certificate not issued / multi-level subdomain)
Cloudflare has no edge certificate for the hostname — the Universal SSL cert is still pending, or the hostname is a second-level…
NET::ERR_CERT_AUTHORITY_INVALID with a Cloudflare Origin Certificate (record not proxied)
Cloudflare Origin CA certificates are only trusted by Cloudflare — visitors reaching the origin directly (grey-cloud record, dire…
HTTP 504 Gateway Timeout
A proxy or gateway waited too long for the upstream server to respond and gave up.
Cloudflare Error 524: A Timeout Occurred
Cloudflare connected to the origin, but the origin didn’t send an HTTP response within 100 seconds.
HTTP 304 Not Modified
The cached copy is still valid, so the server sends no body and the client reuses its cache.
HTTP 400 Bad Request
The server could not understand the request because its syntax, headers or body are malformed or invalid.
HTTP 404 Not Found
The server can’t find anything at the requested URL.
API Error: No such object / resource_missing (resource not found by ID)
The endpoint exists, but the ID you passed — in the URL or as a reference in the body — doesn’t match any record the caller can s…
ERR_CACHE_MISS: Confirm Form Resubmission
You pressed Back/Refresh on a page that was the result of a form POST, so the browser asks before sending the form again.
Mixed Content: The page was loaded over HTTPS, but requested an insecure resource
An HTTPS page tried to load a script, API or image over plain HTTP, and the browser blocked (or warned about) it.
CLEARTEXT communication to host not permitted by network security policy
Android 9+ blocks plain `http://` requests by default; the app tried to call a non-HTTPS URL.
App Transport Security has blocked a cleartext HTTP resource load
iOS blocked an `http://` request (or a weak-TLS HTTPS one) because App Transport Security requires secure connections.
WordPress login: Error: Cookies are blocked or not supported by your browser. You must enable cookies to use WordPress.
WordPress’s test cookie wasn’t returned on login — often a siteurl/home or domain mismatch, caching of wp-login.php, or headers a…
Elementor: The preview could not be loaded / Server Error 500 / Preview Debug
Elementor’s editor couldn’t load the page preview in its iframe — PHP errors, memory limits, mixed URLs, or plugin conflicts.
Cloudflare Error 520: Web Server Returned an Unknown Error
Cloudflare connected to your origin, but the origin returned an empty, unknown or invalid response.
HTTP 414 URI Too Long
The request URL (usually the query string) is longer than the server will accept.
HTTP 508 Loop Detected (Resource Limit Is Reached)
Either the server detected an infinite loop (WebDAV) or — much more often — a cPanel/CloudLinux host is saying your account hit i…
Chrome: This page isn’t working — example.com didn’t send any data. ERR_EMPTY_RESPONSE
The server accepted the connection but closed it without sending any HTTP response — a crash, timeout or misconfigured proxy on t…
Chrome: This page isn’t working — example.com is unable to handle this request. ERR_HTTP2_PROTOCOL_ERROR
The HTTP/2 connection broke a protocol rule — a server, proxy or CDN sent an invalid or oversized frame/header, or closed the str…
Chrome DevTools: net::ERR_CONTENT_LENGTH_MISMATCH — body shorter than the Content-Length header
The server promised a number of bytes in `Content-Length` and sent a different number, so Chrome treats the download as corrupted.
Firefox: Warning: Potential Security Risk Ahead — SEC_ERROR_UNKNOWN_ISSUER (certificate not trusted)
Firefox does not trust the authority that issued the site's certificate — a self-signed certificate, a missing intermediate, or a…
Firefox: Secure Connection Failed — SSL_ERROR_NO_CYPHER_OVERLAP (no common cipher)
Firefox and the server share no TLS cipher suite, so the secure handshake cannot even start.
Firefox: Hmm. We’re having trouble finding that site. / Server not found (DNS_PROBE or NS_ERROR_UNKNOWN_HOST)
Firefox could not resolve the website’s hostname to an IP address — a typo, a DNS problem or no internet.
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