Title: Fatal Error on multisite when network activated
Last modified: September 25, 2026

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# Fatal Error on multisite when network activated

 *  [podpirate](https://wordpress.org/support/users/podpirate/)
 * (@podpirate)
 * [5 days, 11 hours ago](https://wordpress.org/support/topic/fatal-error-on-multisite-when-network-activated/)
 * My Setup:
   PHP 8.4Multisite with SUBDOMAIN_INSTALL = false
 * Site crashes when I activate the plugin in the network admin.
   From the Error 
   Log:
 *     ```wp-block-code
       [25-Sep-2026 09:39:37 UTC] PHP Fatal error: Uncaught Error: Undefined constant "COOKIEPATH" in /wp-content/plugins/youtube-showcase/assets/ext/emd-session/includes/class-emd-wp-session.php:134Stack trace: 0 /wp-content/plugins/youtube-showcase/assets/ext/emd-session/includes/class-emd-wp-session.php(99): EMD_WP_Session->set_cookie() 1 /wp-content/plugins/youtube-showcase/assets/ext/emd-session/includes/class-emd-wp-session.php(58): EMD_WP_Session->__construct() 2 /wp-content/plugins/youtube-showcase/assets/ext/emd-session/includes/emd-wp-session.php(119): EMD_WP_Session::get_instance() 3 /wp-includes/class-wp-hook.php(353): emd_wp_session_write_close('') 4 /wp-includes/class-wp-hook.php(377): WP_Hook->apply_filters(NULL, Array) 5 /wp-includes/plugin.php(523): WP_Hook->do_action(Array) 6 /wp-includes/load.php(1308): do_action('shutdown') 7 [internal function]: shutdown_action_hook() 8 {main}thrown in /wp-content/plugins/youtube-showcase/assets/ext/emd-session/includes/class-emd-wp-session.php on line 134
       ```
   
 * Activating the plugin on a single site however works.
 * Thanks in advance for looking into this!

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## Tags

 * [fatal error](https://wordpress.org/support/topic-tag/fatal-error/)
 * [multisite](https://wordpress.org/support/topic-tag/multisite/)
 * [php](https://wordpress.org/support/topic-tag/php/)

 * 0 replies
 * 1 participant
 * Last reply from: [podpirate](https://wordpress.org/support/users/podpirate/)
 * Last activity: [5 days, 11 hours ago](https://wordpress.org/support/topic/fatal-error-on-multisite-when-network-activated/)
 * Status: not resolved