Syntax & Parse
Parser and tokenization failures.
PHP Error Library
Practical PHP error explanations with causes, diagnosis steps, and modern fixes.
Paste your PHP error
Paste a fatal, warning, SQLSTATE, or cURL message. Paths and line numbers are normalized and are not stored.
PHP errors are often more actionable than they look—if you know which fragment of the message matters. This library focuses on real diagnostic workflows: isolate the message, identify the subsystem, reproduce with the smallest input, then apply a fix that survives PHP upgrades.
Paste a full fatal/warning into the matcher, browse categories such as Composer, Xdebug, PHP-FPM, Apache, nginx, and database/SQLSTATE issues, or filter by PHP version and environment. Every guide starts near the answer—no generic “PHP is popular” filler.
Cross-link into the PHP Error Matcher, Configuration Inspector, and Composer Platform Checker when text analysis helps more than another prose page.
Browse by category
Variables & Constants
Variable scope and constant lookup.
Arrays
Array keys, offsets, and shapes.
Strings
String operations and encoding.
Functions
Function declarations and calls.
Classes & Objects
Object model and property failures.
Namespaces & Autoload
Name resolution and loading.
Type Errors
Runtime type contract violations.
Exceptions
Thrown and uncaught exceptions.
Warnings & Notices
Non-fatal runtime diagnostics.
Deprecated
Version migration deprecations.
Filesystem
File paths, permissions, and streams.
Uploads
HTTP upload handling.
Sessions & Cookies
Session persistence and cookies.
Headers & Output
HTTP output ordering.
JSON
JSON parsing and encoding.
Date & Time
Timezone and date processing.
Memory & Performance
Resource and execution limits.
Composer
Dependency and autoload tooling.
PDO
PDO drivers and statements.
MySQL & MariaDB
Database server errors.
Database Connections
Connection and authentication.
cURL & HTTP
Outbound HTTP transfers.
SSL Certificates
TLS trust and certificates.
PHP Extensions
Extension loading and availability.
PHP-FPM
FastCGI process management.
Apache
Apache PHP integration.
nginx
nginx FastCGI integration.
Xdebug
Xdebug diagnostics.
OPcache
Bytecode cache configuration.
CLI
Command-line PHP.
Cron
Scheduled PHP tasks.
WordPress PHP
WordPress runtime integration.
Laravel PHP
Laravel container and runtime.
Symfony PHP
Symfony services and runtime.
Zend & Laminas
Zend Studio and Laminas runtime.
Legacy PHP
Removed and historical behavior.
PHP Version Compatibility
Cross-version migration failures.
php.ini
PHP configuration directives.
Filter the library
162 matching guides
| Title | Pattern | Severity |
|---|---|---|
| PHP-FPM Primary script unknown | Primary script unknown |
error |
| PHP-FPM server reached pm.max_children | WARNING: [pool www] server reached pm.max_children setting (5), consider raising it |
warning |
| PHP-FPM slowlog permission denied | ERROR: failed to open slowlog (/var/log/php-fpm/www-slow.log): Permission denied |
error |
| post_max_size exceeded and POST is empty | POST Content-Length of %d bytes exceeds the limit of %d bytes |
warning |
| Required parameter follows optional parameter | Deprecated: Required parameter $value follows optional parameter $format in %s on line %d |
notice |
| Return value must be of type | Fatal error: Uncaught TypeError: findName(): Return value must be of type string, null returned in %s on line %d |
fatal |
| SameSite blocks PHP session cookie | Cookie "%s" was rejected because it had the "SameSite=%s" attribute |
warning |
| Secure session cookie missing over HTTP | Set-Cookie: %s; Secure |
warning |
| session_start called while a session is active | Notice: session_start(): Ignoring session_start() because a session is already active |
notice |
| session_start cannot run after output | Warning: session_start(): Session cannot be started after headers have already been sent |
warning |
| session_start open failed | Warning: session_start(): open(/var/lib/php/sessions/sess_abc, O_RDWR) failed: Permission denied |
warning |
| set_exception_handler misses Throwable types | TypeError: Argument #1 ($callback) must be a valid callback |
error |
| SQLSTATE 23000 duplicate entry | SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'ada@example.test' for key 'users.email' |
error |
| SQLSTATE 23000 foreign key constraint fails | SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails |
error |
| SQLSTATE 28000 access denied | SQLSTATE[28000] [1045] Access denied for user 'app'@'%s' (using password: YES) |
fatal |
| SQLSTATE 40001 deadlock found | SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction |
error |
| SQLSTATE 42000 SQL syntax error | SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax |
error |
| SQLSTATE 42S02 table does not exist | SQLSTATE[42S02]: Base table or view not found: 1146 Table 'app.orders' doesn't exist |
error |
| SQLSTATE 42S22 unknown column | SQLSTATE[42S22]: Column not found: 1054 Unknown column 'user_nmae' in 'field list' |
error |
| SQLSTATE HY000 connection refused | SQLSTATE[HY000] [2002] Connection refused |
fatal |
| SQLSTATE HY000 lock wait timeout | SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction |
error |
| SQLSTATE HY000 MySQL socket not found | SQLSTATE[HY000] [2002] No such file or directory |
fatal |
| SQLSTATE HY000 unknown database | SQLSTATE[HY000] [1049] Unknown database 'inventory' |
fatal |
| SQLSTATE HY093 invalid parameter number | SQLSTATE[HY093]: Invalid parameter number: number of bound variables does not match number of tokens |
error |
| SQLSTATE IM001 driver does not support function | SQLSTATE[IM001]: Driver does not support this function: driver does not support setting attributes |
error |
| Symfony service not found | Symfony\\Component\\DependencyInjection\\Exception\\ServiceNotFoundException: You have requested a non-existent service "app.report". |
fatal |
| Too few arguments to function | Fatal error: Uncaught ArgumentCountError: Too few arguments to function sendMail(), 1 passed and exactly 2 expected in %s on line %d |
fatal |
| Too many arguments to function | Fatal error: Uncaught ArgumentCountError: Too many arguments to function render(), 3 passed and exactly 2 expected in %s on line %d |
fatal |
| Trait not found | Fatal error: Trait "App\\Support\\LogsEvents" not found in %s on line %d |
fatal |
| Trying to access array offset on null | Warning: Trying to access array offset on null in %s on line %d |
warning |
| Trying to access array offset on value of type bool | Warning: Trying to access array offset on value of type bool in %s on line %d |
warning |
| Trying to access array offset on value of type int | Warning: Trying to access array offset on value of type int in %s on line %d |
warning |
| Trying to access array offset on value of type string | Warning: Trying to access array offset on value of type string in %s on line %d |
warning |
| TypeError not caught by Exception | Fatal error: Uncaught TypeError: %s in %s:%d |
fatal |
| Uncaught RuntimeException | Fatal error: Uncaught RuntimeException: %s in %s:%d |
fatal |
| Unclosed brace | Parse error: Unclosed '{' on line 9 in %s on line %d |
parse |
| Unclosed parenthesis | Parse error: Unclosed '(' on line 17 in %s on line %d |
parse |
| Undefined array key | Warning: Undefined array key "%s" in %s on line %d |
warning |
| Undefined constant | Fatal error: Uncaught Error: Undefined constant "APP_ENV" in %s on line %d |
fatal |
| Undefined index | Notice: Undefined index: email in %s on line %d |
notice |
| Undefined offset | Notice: Undefined offset: 4 in %s on line %d |
notice |
| Undefined variable | Warning: Undefined variable $userId in %s on line %d |
warning |
| Unexpected identifier | Parse error: syntax error, unexpected identifier "return", expecting ";" in %s on line %d |
parse |
| Unexpected string content | Parse error: syntax error, unexpected single-quoted string "host", expecting "]" in %s on line %d |
parse |
| Unexpected T_STRING | Parse error: syntax error, unexpected T_STRING, expecting ',' or ';' in %s on line %d |
parse |
| Unexpected T_VARIABLE | Parse error: syntax error, unexpected T_VARIABLE in %s on line %d |
parse |
| Unexpected variable | Parse error: syntax error, unexpected variable "$name" in %s on line %d |
parse |
| Unsupported operand types | Fatal error: Uncaught TypeError: Unsupported operand types: array + int in %s on line %d |
fatal |
| Uploaded file exceeds upload_max_filesize | The uploaded file exceeds the upload_max_filesize directive in php.ini |
warning |
| Use of undefined constant assumed string | Notice: Use of undefined constant status - assumed 'status' in %s on line %d |
notice |
Popular / recently updated
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- post_max_size exceeded and POST is empty
- Undefined array key
- Xdebug could not connect to debugging client
- Xdebug Docker client host unreachable
- Xdebug legacy port 9000 mismatch
- 502 Bad Gateway from PHP-FPM
Troubleshooting tools
- Composer Platform Checker Paste composer.json to list PHP constraints and ext-* platform requirements without runni…
- JSON Formatter Validate, pretty-print, and minify JSON in the browser without sending payloads to a serv…
- PHP Configuration Inspector Paste php --ini output or selected directive lines to identify loaded ini files and key l…
- PHP Error Matcher Paste a full PHP error, warning, SQLSTATE, or cURL message to find the best ZendStudio.ne…
FAQ
How should I search for a PHP error?
Paste the distinctive message fragment or the full fatal/warning line. Dynamic paths and line numbers are normalized automatically.
Are these pages replacements for the PHP manual?
No. They are practical troubleshooting guides that complement php.net, Composer, Xdebug, and server documentation.