Plugin could not be activated because it triggered a fatal error 📝 WordPress

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 plugin/theme, or missing PHP extensions.

Seen on: WordPress

Meaning

WordPress catches the error during activation. Enable WP_DEBUG_LOG to see the real error in wp-content/debug.log (function redeclared, class not found, syntax error for your PHP version).

Common causes

  • Plugin requires a newer/older PHP version
  • Function/class name conflict with another plugin
  • Missing PHP extension (intl, mbstring, sodium)
  • Corrupted/incomplete upload

⚡ Quick fix

  1. Turn on WP_DEBUG_LOG and read wp-content/debug.log
  2. Check PHP version requirements
  3. Deactivate conflicting plugins and retry

Detailed fix by platform

WordPress

  1. php
    // wp-config.php
define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);

How to diagnose

  1. Log — debug.log error
  2. PHP — Version vs requirements
  3. Conflicts — Other plugins

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

🧠 Still stuck? Analyze your error

Paste the full message, response headers or stack trace — we'll detect the platform and point to the most likely cause.