Error map

Unable to prepare route for serialization. Uses Closure Laravel: LogicException: Unable to prepare route [dashboard] for serialization. Uses Closure.

Laravel · layer 4, Application & API

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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.

Unable to prepare route for serialization. Uses Closure — Laravel: LogicException: Unable to prepare route [dashboard] for serialization. Uses Closure. (Laravel)Unable to p…Target class does not exist — Laravel: Target class [App\Http\Controllers\X] does not exist. (PHP)Target class does n…Network is unreachable — connect: Network is unreachable (ENETUNREACH) (Linux)Network is unreacha…rest_no_route — WordPress REST API: {"code":"rest_no_route","message":"No route was found matching the URL and request method."} (WordPress)rest_no_routeThe GET method is not supported for route — Laravel: The GET method is not supported for route x. Supported methods: POST (MethodNotAllowedHttpException) (Laravel)The GET method is n…Route [login] not defined — Laravel: Symfony\Component\Routing\Exception\RouteNotFoundException: Route [login] not defined (Laravel)Route [login] not d…Laravel: Allowed memory size exhausted (request) — Laravel/PHP: Allowed memory size of 134217728 bytes exhausted (tried to allocate 20480 bytes) in vendor/laravel/framework (Laravel)Laravel: Allowed me…503 Service Unavailable (maintenance mode stuck) — Laravel: Be right back. / 503 Service Unavailable after php artisan down (Laravel)503 Service Unavail…554 5.4.14 Hop count exceeded - possible mail loop — SMTP: 554 5.4.14 Hop count exceeded - possible mail loop (Email / SMTP)554 5.4.14 Hop coun…The bootstrap/cache directory must be present and writable — Laravel: RuntimeException: The /var/www/bootstrap/cache directory must be present and writable. (Laravel)The bootstrap/cache…404 on all routes except home (public folder / .htaccess) — Laravel on shared hosting: homepage works but every other route returns 404 Not Found (Laravel)404 on all routes e…env() returns null (config cached) — Laravel: .env changes ignored / env('X') returns null after php artisan config:cache (Laravel)env() returns null …Class not found — PHP Fatal error: Uncaught Error: Class "X" not found (PHP)Class not foundNo application encryption key — Laravel: No application encryption key has been specified. (PHP)No application encr…419 Page Expired — Laravel: 419 Page Expired (CSRF token mismatch) (PHP)419 Page Expired404 — HTTP 404 Not Found (HTTP)404405 — HTTP 405 Method Not Allowed (HTTP)405ECONNRESET — Error: socket hang up / read ECONNRESET (API)ECONNRESETNot a valid JSON response — WordPress: Updating failed. The response is not a valid JSON response. (WordPress)Not a valid JSON re…Whitelabel Error Page — Whitelabel Error Page — This application has no explicit mapping for /error (Java)Whitelabel Error Pa…path-to-regexp — TypeError: Missing parameter name at 1 (path-to-regexp) (Node.js)path-to-regexpNo routes matched — No routes matched location "/x" (React)No routes matchedNextRouter was not mounted — Error: NextRouter was not mounted. (React)NextRouter was not …Cannot GET — API Error: Cannot GET /api/... / No route matches / The route could not be found (API)Cannot GETpublickey — Git: Permission denied (publickey). fatal: Could not read from remote repository. (Git)publickeyAADSTS700016 — Azure AD (Entra ID): AADSTS700016 Application not found in the directory (Azure)AADSTS700016401 — HTTP 401 Unauthorized (HTTP)401Allowed memory size exhausted — PHP Fatal error: Allowed memory size of X bytes exhausted (PHP)Allowed memory size…SIGSEGV — Segmentation fault (core dumped) (Linux)SIGSEGVOOM killer — Killed / Out of memory: Killed process (Linux OOM killer) (Linux)OOM killerMaintenance mode — WordPress: Briefly unavailable for scheduled maintenance. Check back in a minute. (WordPress)Maintenance modeYour PHP version does not satisfy requirement — Composer/Laravel: Your Composer dependencies require a PHP version ">= 8.2.0". You are running 8.1.12 (Laravel)Your PHP version do…Command "x" is not defined — Laravel: Symfony\Component\Console\Exception\CommandNotFoundException: Command "make:livewire" is not defined. Did you mean one of these? (Laravel)Command "x" is not …421 4.7.0 Try again later (rate limited) — SMTP: 421 4.7.0 Our system has detected an unusual rate of unsolicited mail originating from your IP address. Mail sent from your IP address has been temporarily rate limited (Email / SMTP)421 4.7.0 Try again…450 4.7.1 Greylisted, please try again later — SMTP: 450 4.7.1 <user@example.com>: Recipient address rejected: Greylisted, see http://postgrey.schweikert.ch/help/example.com.html (Email / SMTP)450 4.7.1 Greyliste…451 4.3.0 Local error in processing — SMTP: 451 4.3.0 Error: queue file write error / 451 Requested action aborted: local error in processing (Email / SMTP)451 4.3.0 Local err…sudoers — user is not in the sudoers file. This incident will be reported. (Linux)sudoersNot allowed — WordPress: Sorry, you are not allowed to access this page. (WordPress)Not allowedsession save path — Warning: session_start(): open(/var/lib/php/sessions/sess_x, O_RDWR) failed: Permission denied (PHP)session save pathStorage files 404: public/storage symlink missing — Laravel: 404 for /storage/file.jpg — symlink(): No such file or directory / The [public/storage] link already exists (Laravel)Storage files 404: …Laravel: Connection could not be established with host — Laravel: Symfony\Component\Mailer\Exception\TransportException: Connection could not be established with host "smtp.mailtrap.io:2525": stream_socket_client(): Unable to connect (Email / SMTP)Laravel: Connection…Attempt to read property "x" on null — Laravel/PHP 8: ErrorException: Attempt to read property "name" on null (Laravel)Attempt to read pro…SQLSTATE[HY000] [1045] Access denied for user — Laravel: SQLSTATE[HY000] [1045] Access denied for user 'forge'@'localhost' (using password: YES) (Laravel)SQLSTATE[HY000] [10…

Directly related (11)

Target class does not existPHP

Laravel: Target class [App\Http\Controllers\X] does not exist.

Laravel’s container couldn’t find the controller or class named in a route or binding.

Network is unreachableLinux

connect: Network is unreachable (ENETUNREACH)

The host has no route to the destination network — no default gateway, interface down, or trying IPv6 without IPv6 connectivity.

rest_no_routeWordPress

WordPress REST API: {"code":"rest_no_route","message":"No route was found matching the URL and request method."}

The REST endpoint doesn’t exist for that URL and HTTP method — wrong namespace/route, plugin not active, or route registered too…

The GET method is not supported for routeLaravel

Laravel: The GET method is not supported for route x. Supported methods: POST (MethodNotAllowedHttpException)

The URL exists, but not for the HTTP method used — e.g. opening a POST-only route in the browser, or a form sending GET.

Route [login] not definedLaravel

Laravel: Symfony\Component\Routing\Exception\RouteNotFoundException: Route [login] not defined

Code called route('name') for a route name that doesn’t exist — very often route('login') from the auth middleware in API-only ap…

Laravel: Allowed memory size exhausted (request)Laravel

Laravel/PHP: Allowed memory size of 134217728 bytes exhausted (tried to allocate 20480 bytes) in vendor/laravel/framework

A request (or artisan job) used more memory than PHP's `memory_limit` allows.

503 Service Unavailable (maintenance mode stuck)Laravel

Laravel: Be right back. / 503 Service Unavailable after php artisan down

The application is in maintenance mode — after `php artisan down` (or a failed deploy) it was never brought back up.

554 5.4.14 Hop count exceeded - possible mail loopEmail / SMTP

SMTP: 554 5.4.14 Hop count exceeded - possible mail loop

The message passed through too many mail servers (usually over 25), which almost always means two systems forward mail to each ot…

The bootstrap/cache directory must be present and writableLaravel

Laravel: RuntimeException: The /var/www/bootstrap/cache directory must be present and writable.

Laravel can't write its compiled cache files because the folder is missing or has the wrong permissions/owner.

404 on all routes except home (public folder / .htaccess)Laravel

Laravel on shared hosting: homepage works but every other route returns 404 Not Found

The web server isn't sending requests to `public/index.php`, so only the root path works — the rewrite rules aren't active.

env() returns null (config cached)Laravel

Laravel: .env changes ignored / env('X') returns null after php artisan config:cache

After `config:cache`, Laravel no longer reads `.env`, so `env()` calls outside config files return null and edits to `.env` have…

Two steps away (31)

Class not foundPHP

PHP Fatal error: Uncaught Error: Class "X" not found

PHP couldn’t load the class — autoloading failed, the namespace is wrong, or the dependency isn’t installed.

No application encryption keyPHP

Laravel: No application encryption key has been specified.

Laravel’s APP_KEY is missing, so it can’t encrypt sessions and cookies.

419 Page ExpiredPHP

Laravel: 419 Page Expired (CSRF token mismatch)

Laravel rejected a POST because the CSRF token was missing, expired or didn’t match the session.

404HTTP

HTTP 404 Not Found

The server can’t find anything at the requested URL.

405HTTP

HTTP 405 Method Not Allowed

The URL exists, but it doesn’t accept the HTTP method you used (e.g. POST to a GET-only route).

ECONNRESETAPI

Error: socket hang up / read ECONNRESET

The other side closed the TCP connection abruptly while your client was still using it.

Not a valid JSON responseWordPress

WordPress: Updating failed. The response is not a valid JSON response.

The block editor saved via the REST API but got HTML or an error page back — broken permalinks, a security plugin/WAF, or PHP out…

Whitelabel Error PageJava

Whitelabel Error Page — This application has no explicit mapping for /error

Spring Boot’s default error page — the request hit no controller mapping (404) or a controller threw (500).

path-to-regexpNode.js

TypeError: Missing parameter name at 1 (path-to-regexp)

An Express 5 (path-to-regexp v8) route uses old wildcard syntax like '*' or '/:id?'.

No routes matchedReact

No routes matched location "/x"

React Router found no route definition for the current URL.

NextRouter was not mountedReact

Error: NextRouter was not mounted.

next/router’s useRouter was used inside the App Router (app/ directory), which uses next/navigation instead.

Cannot GETAPI

API Error: Cannot GET /api/... / No route matches / The route could not be found

The server has no route for this URL and HTTP method combination — the endpoint path, API version prefix or method is wrong.

publickeyGit

Git: Permission denied (publickey). fatal: Could not read from remote repository.

SSH authentication to GitHub/GitLab/Bitbucket failed — no key, wrong key, or the key isn’t added to your account.

AADSTS700016Azure

Azure AD (Entra ID): AADSTS700016 Application not found in the directory

The client ID in your sign-in request doesn’t exist in the tenant you’re authenticating against.

401HTTP

HTTP 401 Unauthorized

The request has no valid authentication credentials — you need to log in or send a valid token.

Allowed memory size exhaustedPHP

PHP Fatal error: Allowed memory size of X bytes exhausted

The script tried to use more memory than PHP’s `memory_limit` allows.

SIGSEGVLinux

Segmentation fault (core dumped)

A program accessed memory it wasn’t allowed to, and the kernel killed it with SIGSEGV (exit code 139).

OOM killerLinux

Killed / Out of memory: Killed process (Linux OOM killer)

The kernel ran out of memory and killed a process to recover — the program just prints “Killed” (exit code 137).

Maintenance modeWordPress

WordPress: Briefly unavailable for scheduled maintenance. Check back in a minute.

An update was interrupted and WordPress left its `.maintenance` file behind, so the site stays in maintenance mode.

Your PHP version does not satisfy requirementLaravel

Composer/Laravel: Your Composer dependencies require a PHP version ">= 8.2.0". You are running 8.1.12

The installed dependencies need a newer PHP than the one running the app (CLI or web server).

Command "x" is not definedLaravel

Laravel: Symfony\Component\Console\Exception\CommandNotFoundException: Command "make:livewire" is not defined. Did you mean one of these?

`php artisan` doesn't know the command you typed — typo, missing package or an unregistered service provider.

421 4.7.0 Try again later (rate limited)Email / SMTP

SMTP: 421 4.7.0 Our system has detected an unusual rate of unsolicited mail originating from your IP address. Mail sent from your IP address has been temporarily rate limited

The receiving server (often Gmail or Outlook) is temporarily throttling your mail because the volume or reputation of your sendin…

450 4.7.1 Greylisted, please try again laterEmail / SMTP

SMTP: 450 4.7.1 <user@example.com>: Recipient address rejected: Greylisted, see http://postgrey.schweikert.ch/help/example.com.html

The recipient server deliberately rejected the first delivery attempt from an unknown sender (greylisting) and expects a legitima…

451 4.3.0 Local error in processingEmail / SMTP

SMTP: 451 4.3.0 Error: queue file write error / 451 Requested action aborted: local error in processing

The server hit an internal problem (disk, database, content filter, DNS) while handling your message and asked you to retry later.

sudoersLinux

user is not in the sudoers file. This incident will be reported.

Your account isn’t allowed to use sudo.

Not allowedWordPress

WordPress: Sorry, you are not allowed to access this page.

Your user role lacks the capability for that admin screen — or the database table prefix / user capabilities are out of sync afte…

session save pathPHP

Warning: session_start(): open(/var/lib/php/sessions/sess_x, O_RDWR) failed: Permission denied

PHP can’t write session files to the configured session.save_path.

Storage files 404: public/storage symlink missingLaravel

Laravel: 404 for /storage/file.jpg — symlink(): No such file or directory / The [public/storage] link already exists

Uploaded files stored in `storage/app/public` aren't reachable because the `public/storage` symlink doesn't exist or points to th…

Laravel: Connection could not be established with hostEmail / SMTP

Laravel: Symfony\Component\Mailer\Exception\TransportException: Connection could not be established with host "smtp.mailtrap.io:2525": stream_socket_client(): Unable to connect

Laravel's mailer could not connect to the SMTP host configured in `.env`.

Attempt to read property "x" on nullLaravel

Laravel/PHP 8: ErrorException: Attempt to read property "name" on null

You accessed a property on a value that is `null`, typically an empty relationship or a query that found nothing.

SQLSTATE[HY000] [1045] Access denied for userLaravel

Laravel: SQLSTATE[HY000] [1045] Access denied for user 'forge'@'localhost' (using password: YES)

MySQL rejected the username/password configured in Laravel's `.env`.