Title: Fatal error: Uncaught Error: Call to undefined function array_key_first()
Last modified: November 1, 2021

---

# Fatal error: Uncaught Error: Call to undefined function array_key_first()

 *  [Said Erraoudy](https://wordpress.org/support/users/erraoudy/)
 * (@erraoudy)
 * [4 years, 7 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-array_key_first/)
 * Fatal error: Uncaught Error: Call to undefined function array_key_first() in /
   home/cooknus/public_html/seo/wp-content/plugins/wp-pop-up/classes/class-wp-popup.
   php:671 Stack trace: #0 /home/cooknus/public_html/seo/wp-content/plugins/wp-pop-
   up/classes/class-wp-popup.php(618): WP_Popup->which_popup_to_display() #1 /home/
   cooknus/public_html/seo/wp-includes/class-wp-hook.php(303): WP_Popup->post_loop(
   Object(WP)) #2 /home/cooknus/public_html/seo/wp-includes/class-wp-hook.php(327):
   WP_Hook->apply_filters(NULL, Array) #3 /home/cooknus/public_html/seo/wp-includes/
   plugin.php(518): WP_Hook->do_action(Array) #4 /home/cooknus/public_html/seo/wp-
   includes/class-wp.php(763): do_action_ref_array(‘wp’, Array) #5 /home/cooknus/
   public_html/seo/wp-includes/functions.php(1291): WP->main(”) #6 /home/cooknus/
   public_html/seo/wp-blog-header.php(16): wp() #7 /home/cooknus/public_html/seo/
   index.php(17): require(‘/home/cooknus/p…’) #8 {main} thrown in /home/cooknus/
   public_html/seo/wp-content/plugins/wp-pop-up/classes/class-wp-popup.php on line
   671

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

 *  Plugin Author [cornershop](https://wordpress.org/support/users/cornershop/)
 * (@cornershop)
 * [4 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-array_key_first/#post-15316262)
 * [@erraoudy](https://wordpress.org/support/users/erraoudy/) Very sorry we missed
   this report in our review queue! Thanks very much for alerting us to this. This
   isn’t a report that we’ve seen from others, but I’ve filed a task with our team
   to try and replicate the same error. If you would still find it helpful to reach
   out, you can contact us at [support@cornershopcreative.com](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-array_key_first/support@cornershopcreative.com?output_format=md)
   and we can troubleshoot your error message by checking out your site directly.
   Best wishes! (Chelsea)
 *  Plugin Author [cornershop](https://wordpress.org/support/users/cornershop/)
 * (@cornershop)
 * [4 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-array_key_first/#post-15347780)
 * Following up! We’re adding tasks to improve our PHP version checking and documentation,
   since this error is caused by using PHP versions older than 7.3. To avoid this,
   you’ll want to use PHP 7.3, and we’ll work on adding some checks to guard against
   this in the future. Thank you again! (Chelsea)

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

The topic ‘Fatal error: Uncaught Error: Call to undefined function array_key_first()’
is closed to new replies.

 * ![](https://ps.w.org/wp-pop-up/assets/icon.svg?rev=2010741)
 * [WP Popup](https://wordpress.org/plugins/wp-pop-up/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/wp-pop-up/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/wp-pop-up/)
 * [Active Topics](https://wordpress.org/support/plugin/wp-pop-up/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/wp-pop-up/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/wp-pop-up/reviews/)

 * 2 replies
 * 2 participants
 * Last reply from: [cornershop](https://wordpress.org/support/users/cornershop/)
 * Last activity: [4 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-call-to-undefined-function-array_key_first/#post-15347780)