Title: Cannot activate
Last modified: March 22, 2022

---

# Cannot activate

 *  [Steve North](https://wordpress.org/support/users/tex0gen/)
 * (@tex0gen)
 * [4 years, 2 months ago](https://wordpress.org/support/topic/cannot-activate-58/)
 * Triggers a fatal PHP error:
 * `Fatal error: Uncaught ArgumentCountError: array_merge() does not accept unknown
   named parameters in public_html/wp-content/plugins/wp-criticalcss/lib/WP/CriticalCSS/
   Request.php:119`
    -  This topic was modified 4 years, 2 months ago by [Steve North](https://wordpress.org/support/users/tex0gen/).
    -  This topic was modified 4 years, 2 months ago by [Steve North](https://wordpress.org/support/users/tex0gen/).

Viewing 2 replies - 1 through 2 (of 2 total)

 *  Plugin Author [Derrick Hammer](https://wordpress.org/support/users/pcfreak30/)
 * (@pcfreak30)
 * [4 years, 2 months ago](https://wordpress.org/support/topic/cannot-activate-58/#post-15485042)
 * From what I can see, this is a PHP 8 issue. The plugin has not been tested with
   this version.
 * Sorry, but thanks for reporting.
 *  Thread Starter [Steve North](https://wordpress.org/support/users/tex0gen/)
 * (@tex0gen)
 * [4 years, 2 months ago](https://wordpress.org/support/topic/cannot-activate-58/#post-15485433)
 * The site is indeed running PHP8. It’s been released for over a year (18 months)
   so I’d have expected it to have been tested by now.

Viewing 2 replies - 1 through 2 (of 2 total)

The topic ‘Cannot activate’ is closed to new replies.

 * ![](https://s.w.org/plugins/geopattern-icon/wp-criticalcss.svg)
 * [WP Critical CSS](https://wordpress.org/plugins/wp-criticalcss/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/wp-criticalcss/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/wp-criticalcss/)
 * [Active Topics](https://wordpress.org/support/plugin/wp-criticalcss/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/wp-criticalcss/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/wp-criticalcss/reviews/)

 * 2 replies
 * 2 participants
 * Last reply from: [Steve North](https://wordpress.org/support/users/tex0gen/)
 * Last activity: [4 years, 2 months ago](https://wordpress.org/support/topic/cannot-activate-58/#post-15485433)