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

**Code:** `Plugin could not be activated because it triggered a fatal error` · **Category:** WordPress · **Seen on:** WordPress

Activating the plugin caused a PHP fatal error — usually PHP version incompatibility, a conflict with another plugin/theme, or missing PHP extensions.

## 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

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Source: [WhatIsMyError](https://whatismyerror.com/errors/wordpress/plugin-could-not-be-activated-fatal-error)