Error map
424 HTTP 424 Failed Dependency
HTTP · layer 2, Network
Centre: this error. First ring: errors it is linked with (7). 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 (7)
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 422 Unprocessable Content
The request is well-formed, but the data fails validation (e.g. invalid email, missing required field).
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.
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 409 Conflict
The request conflicts with the current state of the resource — e.g. a duplicate or an edit based on an outdated version.
HTTP 507 Insufficient Storage
The server can’t store what’s needed to complete the request — the disk, quota or mailbox is full.
HTTP 423 Locked
The resource is locked, so the change was refused — common with WebDAV files and some APIs that lock records during processing.
Two steps away (21)
HTTP 404 Not Found
The server can’t find anything at the requested URL.
SyntaxError: Unexpected token < in JSON at position 0
`JSON.parse()` / `response.json()` received something that isn’t JSON — very often an HTML error page.
GraphQL: Cannot query field "x" on type "Y"
The query asks for a field that doesn’t exist in the server’s schema (or isn’t available on that type).
HTTP 400 Bad Request
The server could not understand the request because its syntax, headers or body are malformed or invalid.
HTTP 415 Unsupported Media Type
The server refuses the request because the body’s Content-Type isn’t one it accepts.
MySQL ERROR 1406: Data too long for column
The value is longer than the column allows (e.g. 300 characters into VARCHAR(255)), and strict mode rejects it instead of truncat…
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…
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.
MySQL ERROR 1062 (23000): Duplicate entry for key
An INSERT/UPDATE would create a duplicate value in a PRIMARY or UNIQUE key.
HTTP 412 Precondition Failed
A conditional request header (If-Match, If-Unmodified-Since) didn’t match the current state of the resource.
HTTP 428 Precondition Required
The server requires a conditional request (If-Match / If-Unmodified-Since) to prevent lost updates, and you didn’t send one.
no space left on device (Docker / Linux)
The disk (or inode table) is full — Docker images, build cache, logs and volumes are common culprits.
HTTP 429 Too Many Requests
You’ve hit a rate limit — too many requests in a given time window. Slow down and retry later.
HTTP 500 Internal Server Error
The server hit an unexpected condition — usually an unhandled exception or misconfiguration in the application.
HTTP 403 Forbidden
The server understood the request but refuses to authorize it — you (or the server process) are not allowed to access this resour…
API Error: Resource already exists (ALREADY_EXISTS / resource_already_exists / 409)
The create request was refused because an object with the same unique identity — name, email, external ID — already exists.
API Error: Invalid state transition — operation not allowed in the resource’s current state
The request is valid, but the object is in a state where this action isn’t allowed — cancelling something already completed, refu…
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