{"id":19029126,"date":"2026-09-25T09:49:17","date_gmt":"2026-09-25T09:49:17","guid":{"rendered":"https:\/\/wordpress.org\/support\/topic\/fatal-error-on-multisite-when-network-activated\/"},"modified":"2026-09-25T09:49:17","modified_gmt":"2026-09-25T09:49:17","slug":"fatal-error-on-multisite-when-network-activated","status":"publish","type":"topic","link":"https:\/\/wordpress.org\/support\/topic\/fatal-error-on-multisite-when-network-activated\/","title":{"rendered":"Fatal Error on multisite when network activated"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">My Setup:<br \/>PHP 8.4<br \/>Multisite with SUBDOMAIN_INSTALL = false<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Site crashes when I activate the plugin in the network admin.<br \/>From the Error Log:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>&#091;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:134<br \/>Stack trace: 0 \/wp-content\/plugins\/youtube-showcase\/assets\/ext\/emd-session\/includes\/class-emd-wp-session.php(99): EMD_WP_Session-&gt;set_cookie() 1 \/wp-content\/plugins\/youtube-showcase\/assets\/ext\/emd-session\/includes\/class-emd-wp-session.php(58): EMD_WP_Session-&gt;__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-&gt;apply_filters(NULL, Array) 5 \/wp-includes\/plugin.php(523): WP_Hook-&gt;do_action(Array) 6 \/wp-includes\/load.php(1308): do_action('shutdown') 7 &#091;internal function]: shutdown_action_hook() 8 {main}<br \/><br \/>thrown in \/wp-content\/plugins\/youtube-showcase\/assets\/ext\/emd-session\/includes\/class-emd-wp-session.php on line 134<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Activating the plugin on a single site however works.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Thanks in advance for looking into this!<\/p>\n","protected":false},"template":"","class_list":["post-19029126","topic","type-topic","status-publish","hentry","topic-tag-fatal-error","topic-tag-multisite","topic-tag-php"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic\/19029126","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic"}],"about":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic\/19029126\/revisions"}],"wp:attachment":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/media?parent=19029126"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}