| Critical error |
WordPress: There Has Been a Critical Error on This Website |
A PHP fatal error (usually from a plugin or theme) stopped WordPress; the real error is in the debug log or r… |
| There was an error trying to send your message |
Contact Form 7: There was an error trying to send your message. Please try again later. |
The form submitted, but wp_mail() failed to send — the server can’t send mail or the mail settings are wrong. |
| Call to undefined function create_function() |
WordPress on PHP 8: Fatal error: Uncaught Error: Call to undefined function create_function() / each() |
An old plugin/theme uses functions removed in PHP 8 (create_function, each), so the site breaks after a PHP u… |
| 403 Forbidden wp-admin |
WordPress: 403 Forbidden on wp-admin, wp-login.php or admin-ajax.php |
The server or a security layer refused access to WordPress admin URLs — file permissions, a security plugin/W… |
| Download failed |
WordPress: Download failed. A valid URL was not provided / cURL error 60 / Could not resolve host: downloads.wordpress.org |
WordPress couldn’t download an update package — outbound HTTP blocked, DNS failure, SSL CA issues, or a premi… |
| The REST API encountered an error |
Site Health: The REST API encountered an error / Your site could not complete a loopback request (cURL error 28) |
WordPress couldn’t call itself over HTTP — needed for the block editor, cron, plugin/theme editors and Site H… |
| Installation failed: Could not create directory |
WordPress: Installation failed: Could not create directory (plugin/theme install or update) |
WordPress can’t write to wp-content/plugins, themes or upgrade — ownership/permissions or disk space. |
| XML-RPC server accepts POST requests only |
WordPress: XML-RPC server accepts POST requests only (xmlrpc.php) |
You opened xmlrpc.php in a browser (GET) — it’s an API endpoint, not a page. Heavy POST traffic to it usually… |
| Error establishing a Redis connection |
WordPress: Error establishing a Redis connection (object cache) |
The persistent object cache drop-in (object-cache.php) can’t connect to Redis, so the whole site fails. |
| This block contains unexpected or invalid content |
WordPress: This block contains unexpected or invalid content. Attempt Block Recovery |
The saved HTML of a block doesn’t match what the block’s current save function produces — after a plugin upda… |
| There was an error processing your order |
WooCommerce: There was an error processing your order. Please check for any charges in your payment method / Error processing checkout. Please try again. |
Checkout failed server-side — payment gateway error, nonce/session issue from caching, or a PHP error from a… |
| SMTP Error: Could not authenticate |
WordPress / PHPMailer: SMTP Error: Could not authenticate / SMTP connect() failed |
The SMTP server rejected the login or couldn’t be reached — wrong credentials, app passwords required, wrong… |
| file type is not permitted |
WordPress: Sorry, you are not allowed to upload this file type / Sorry, this file type is not permitted for security reasons |
WordPress blocked the upload because the file extension/MIME type isn’t in its allowed list (SVG, JSON, WEBP… |
| Not a valid JSON response |
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 pl… |
| The preview could not be loaded |
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 p… |
| Maintenance mode |
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… |
| Call to undefined function (WordPress) |
WordPress: Fatal error: Uncaught Error: Call to undefined function wp_get_current_user() / add_action() / get_header() |
Code called a WordPress function before WordPress loaded, or a theme/plugin file was opened directly. |
| You are probably offline |
WordPress: Updating failed. You are probably offline. |
The block editor’s save request to the REST API failed — network blip, REST API blocked, or the server return… |
| missing the MySQL extension |
WordPress: Your PHP installation appears to be missing the MySQL extension which is required by WordPress |
PHP doesn’t have the mysqli extension loaded, so WordPress can’t talk to the database. |
| An automated WordPress update has failed |
An automated WordPress update has failed to complete - please attempt the update again now |
A background core update stopped mid-way, so WordPress asks you to run it again (and may be stuck in maintena… |
| Another update is currently in progress |
WordPress: Another update is currently in progress. |
WordPress thinks an update is running because the core_updater.lock option exists — usually left behind by a… |
| DB connection |
WordPress: Error Establishing a Database Connection |
WordPress can’t connect to its MySQL/MariaDB database with the credentials in wp-config.php, or the database… |
| One or more database tables are unavailable |
WordPress: One or more database tables are unavailable. The database may need to be repaired. |
WordPress can’t read one or more of its tables — they’re crashed (MyISAM), missing, or the table prefix in wp… |
| Plugin could not be activated because it triggered a fatal error |
WordPress: Plugin could not be activated because it triggered a fatal error |
Activating the plugin caused a PHP fatal error — usually PHP version incompatibility, a conflict with another… |
| requires at least PHP |
WordPress: Your server is running PHP version 7.2 but WordPress 6.x requires at least 7.4 / This plugin requires a newer version of PHP |
WordPress core, a plugin or a theme needs a newer PHP than the server runs. |
| The editor has encountered an unexpected error |
WordPress block editor: The editor has encountered an unexpected error (Attempt Recovery / Copy Error) |
A JavaScript error broke the block editor — usually a plugin/theme block script conflict, cached old scripts,… |
| Cookies are blocked |
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-log… |
| 404 except homepage |
WordPress: 404 Not Found on every page except the homepage (permalinks / .htaccess / Nginx rules) |
Pretty permalinks aren’t being routed to index.php — .htaccess is missing/ignored (Apache) or Nginx lacks try… |
| Are you sure you want to do this? |
WordPress: Are you sure you want to do this? Please try again. (nonce check failed) |
A WordPress security nonce didn’t validate — the page was open too long, cached, or a plugin/theme form is br… |
| Missed schedule |
WordPress: Missed schedule — scheduled posts not publishing (WP-Cron not running) |
WP-Cron didn’t fire at the scheduled time, so scheduled posts and tasks (backups, emails, WooCommerce jobs) a… |
| The uploaded file could not be moved to |
WordPress: The uploaded file could not be moved to wp-content/uploads/2026/10 |
PHP received the upload but couldn’t move it from the temp directory into uploads — permissions, disk space,… |
| Unable to create directory |
WordPress: Unable to create directory wp-content/uploads/2026/10. Is its parent directory writable by the server? |
PHP can’t write to wp-content/uploads — wrong ownership/permissions, a wrong upload path, full disk, or open_… |
| rest_forbidden |
WordPress REST API: {"code":"rest_forbidden","message":"Sorry, you are not allowed to do that."} (401/403) |
The REST request isn’t authenticated or the user lacks the capability required by the route’s permission_call… |
| ERR_TOO_MANY_REDIRECTS (WordPress) |
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,… |
| Post-processing of the image failed |
WordPress: Post-processing of the image failed likely because the server is busy or does not have enough resources |
The image uploaded but WordPress couldn’t generate its resized versions — memory/CPU limits or Imagick proble… |
| Link expired |
WordPress: The link you followed has expired |
Usually an upload (theme, plugin, media) larger than PHP’s upload/post limits — WordPress receives an empty r… |
| The theme is missing the style.css stylesheet |
WordPress: The package could not be installed. The theme is missing the style.css stylesheet |
The uploaded theme zip doesn’t have style.css at its top level — usually a full download package or a plugin… |
| There doesn't seem to be a wp-config.php file |
WordPress: There doesn't seem to be a wp-config.php file. I need this before we can get started |
WordPress can’t find wp-config.php, so it starts the installer — on an existing site that means the file was… |
| Please enter your FTP credentials |
To perform the requested action, WordPress needs to access your web server. Please enter your FTP credentials to proceed |
WordPress can’t write directly to its files (ownership differs from the PHP user), so it falls back to asking… |
| Sorry, your session has expired |
WooCommerce: Sorry, your session has expired. Return to shop |
WooCommerce lost the customer’s cart session — usually because checkout/cart pages are cached or cookies are… |
| HTTP error (media upload) |
WordPress Media: “HTTP error.” when uploading images |
The upload request failed on the server — memory or timeout during image processing, upload size limits, ModS… |
| rest_cookie_invalid_nonce |
WordPress REST API: {"code":"rest_cookie_invalid_nonce","message":"Cookie check failed"} (403) |
A cookie-authenticated REST request carried a missing or stale X-WP-Nonce — common with cached pages or after… |
| rest_no_route |
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 r… |
| Plugin file does not exist |
WordPress: The plugin x has been deactivated due to an error: Plugin file does not exist. |
An active plugin’s main file can’t be found — the plugin folder was renamed, deleted or moved outside WordPre… |
| This does not seem to be a WordPress installation |
WP-CLI: Error: This does not seem to be a WordPress installation. Pass --path=`path/to/wordpress` or run `wp core download` |
WP-CLI couldn’t find WordPress in the current directory (or the --path given). |
| No valid plugins were found |
The package could not be installed. No valid plugins were found |
The uploaded zip doesn’t contain a plugin main file with a plugin header at the expected level — often a zip… |
| Destination folder already exists |
WordPress: Destination folder already exists. Plugin installation failed |
A folder with the plugin/theme’s name already exists in wp-content, usually from a failed or partial previous… |
| Index of / |
WordPress site shows "Index of /" (directory listing instead of the site) |
The web server isn’t using index.php as the directory index, or index.php is missing — so it lists files inst… |
| Not allowed |
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… |
| The parent theme is missing |
WordPress: The parent theme is missing. Please install the "x" parent theme. |
A child theme is active (or installed) but its parent theme isn’t installed, or the Template header doesn’t m… |