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WordPress Bug Fix Library

Server, PHP & API Errors

A practical guide from the WP Fix team.

Server, PHP and API failures: 403/500/502/503/504, fatal errors, memory, cURL, REST, loopback and WP-Cron.

Start with the symptom

Choose the closest visible error below. Each guide explains likely causes, evidence to collect and a controlled repair path. If the site is business-critical, the dedicated bug-fix request form sends the exact issue directly into the technical intake.

Focused troubleshooting guide

WordPress Critical Error

Fix the “There has been a critical error on this website” message with controlled WordPress diagnostics for plugins, themes, PHP, memory and failed updates.

Open guide →Focused troubleshooting guide

WordPress 500 Internal Server Error

Diagnose and fix WordPress 500 Internal Server Error problems caused by PHP fatals, .htaccess rules, permissions, server limits, plugins or themes.

Open guide →Focused troubleshooting guide

WordPress White Screen of Death

Fix a blank white WordPress screen by tracing PHP fatal errors, memory problems, plugin/theme conflicts, output failures and broken updates.

Open guide →Focused troubleshooting guide

WordPress PHP Fatal Error

Fix WordPress PHP fatal errors including undefined functions, class conflicts, TypeErrors, incompatible method signatures and PHP version problems.

Open guide →Focused troubleshooting guide

WordPress Memory Exhausted Error

Fix WordPress “Allowed memory size exhausted” errors by identifying high-memory plugins, queries, imports, image jobs and PHP/WP memory configuration.

Open guide →Focused troubleshooting guide

WordPress 403 Forbidden Error

Fix a WordPress 403 Forbidden error caused by permissions, security rules, .htaccess, CDN/WAF blocks, plugins or server configuration.

Open guide →Focused troubleshooting guide

WordPress 502 Bad Gateway

Fix WordPress 502 Bad Gateway errors caused by PHP-FPM, reverse proxies, upstream timeouts, overloaded workers, plugins or server failures.

Open guide →Focused troubleshooting guide

WordPress 503 Service Unavailable

Fix WordPress 503 Service Unavailable errors caused by maintenance, resource limits, PHP workers, plugins, rate limiting or hosting outages.

Open guide →Focused troubleshooting guide

WordPress 504 Gateway Timeout

Fix WordPress 504 Gateway Timeout errors by tracing slow PHP, database queries, external APIs, imports, plugins and proxy timeout failures.

Open guide →Focused troubleshooting guide

WordPress Maximum Execution Time Exceeded

Fix WordPress “Maximum execution time exceeded” errors from imports, backups, image processing, plugins, cron jobs or slow PHP code.

Open guide →Focused troubleshooting guide

WordPress PHP Syntax Error

Fix WordPress PHP parse/syntax errors after code edits, plugin/theme updates or snippets, including unexpected token and unexpected end errors.

Open guide →Focused troubleshooting guide

WordPress cURL Error 28

Fix WordPress cURL error 28 / connection timed out problems affecting REST API, Site Health, updates, webhooks and external services.

Open guide →Focused troubleshooting guide

WordPress cURL Error 60 SSL Certificate Problem

Fix WordPress cURL error 60 SSL certificate problems affecting API calls, updates, webhooks and external HTTPS requests.

Open guide →Focused troubleshooting guide

WordPress REST API Error

Fix WordPress REST API errors that break Gutenberg, Elementor, WooCommerce, Site Health, plugins and integrations with 401, 403, 404 or 500 responses.

Open guide →Focused troubleshooting guide

WordPress Loopback Request Failed

Fix WordPress loopback request failures in Site Health caused by DNS, SSL, authentication, firewall, cache or server configuration.

Open guide →Focused troubleshooting guide

WordPress Cron Not Working

Fix WordPress WP-Cron problems causing missed schedules, delayed emails, WooCommerce tasks, backups and plugin jobs.

Open guide →Focused troubleshooting guide

WordPress AJAX 400 Bad Request

Fix WordPress admin-ajax.php 400 Bad Request errors caused by missing actions, invalid nonces, plugin callbacks, cache, WAF or malformed requests.

Open guide →Focused troubleshooting guide

WordPress admin-ajax.php 403 Forbidden

Fix WordPress admin-ajax.php 403 Forbidden errors caused by WAF/ModSecurity, security plugins, permissions, nonces, authentication or rate limiting.

Open guide →

Why these errors belong together

Server, PHP and API failures: 403/500/502/503/504, fatal errors, memory, cURL, REST, loopback and WP-Cron. The same symptom can be caused by WordPress code, PHP, JavaScript, database state, hosting, cache, a CDN/WAF or a third-party integration. Grouping related symptoms makes it easier to compare likely causes without treating every failure as the same generic “plugin conflict.”

Need the live site repaired?

Use the dedicated WordPress Bug Fix Request. Share the URL, exact error, urgency and what changed before the problem started. Credentials are requested separately only if the diagnosis requires access.

Request a WordPress Bug Fix

Continue investigating

WordPress 500 Internal Server Error ↗Elementor 500 Server Error ↗WordPress PHP Fatal Error ↗

Technical support

Skip trial-and-error on a production site.

Send the exact symptom and we’ll use it as the starting point for diagnosis.

Request professional troubleshooting

Your next step

Tell us what
needs attention.

Start with the site URL and what you are seeing. The WP Fix team will review the details and reply by email.

  1. We clarify the issue and the outcome you need.
  2. We confirm scope, availability and price.
  3. We agree on access and the work before making changes.

No passwords needed to start. Timing depends on the issue and current availability.

About: Server, PHP & API Errors

Please do not include passwords or access keys. We use your details to respond to this enquiry. Web3Forms processes the submission.