Prime Mover 1.9.2 plus WP Multi Network causes fatal error in Site Editor

Hi, since the Prime Mover update from two days ago, we’re getting 500 Internal Server error when accessing the Site Editor. The following error shows in our logs.

[06-Nov-2023 16:32:03 UTC] PHP Fatal error:  Uncaught Error: Undefined constant "SECURE_AUTH_COOKIE" in /var/www/xxx/htdocs/wp-includes/pluggable.php:929
Stack trace:
#0 /var/www/xxx/htdocs/wp-includes/pluggable.php(694): wp_parse_auth_cookie()
#1 /var/www/xxx/htdocs/wp-includes/class-wp-hook.php(310): wp_validate_auth_cookie()
#2 /var/www/xxx/htdocs/wp-includes/plugin.php(205): WP_Hook->apply_filters()
#3 /var/www/xxx/htdocs/wp-includes/user.php(3622): apply_filters()
#4 /var/www/xxx/htdocs/wp-includes/pluggable.php(70): _wp_get_current_user()
#5 /var/www/xxx/htdocs/wp-includes/l10n.php(98): wp_get_current_user()
#6 /var/www/xxx/htdocs/wp-includes/l10n.php(152): get_user_locale()
#7 /var/www/xxx/htdocs/wp-includes/l10n.php(1300): determine_locale()
#8 /var/www/xxx/htdocs/wp-includes/l10n.php(1331): _load_textdomain_just_in_time()
#9 /var/www/xxx/htdocs/wp-includes/l10n.php(185): get_translations_for_domain()
#10 /var/www/xxx/htdocs/wp-includes/l10n.php(330): translate()
#11 /var/www/xxx/htdocs/wp-content/mu-plugins/wp-multi-network/includes/classes/class-wp-ms-networks-admin.php(176): esc_html__()
#12 /var/www/xxx/htdocs/wp-content/mu-plugins/wp-multi-network/includes/classes/class-wp-ms-networks-admin.php(35): WP_MS_Networks_Admin->set_feedback_strings()
#13 /var/www/xxx/htdocs/wp-content/mu-plugins/wpmn-loader.php(159): WP_MS_Networks_Admin->__construct()
#14 /var/www/xxx/htdocs/wp-content/mu-plugins/wpmn-loader.php(106): WPMN_Loader->includes()
#15 /var/www/xxx/htdocs/wp-content/mu-plugins/wpmn-loader.php(218): WPMN_Loader->__construct()
#16 /var/www/xxx/htdocs/wp-content/mu-plugins/wpmn-loader.php(190): wpmn()
#17 /var/www/xxx/htdocs/wp-includes/class-wp-hook.php(310): setup_multi_network()
#18 /var/www/xxx/htdocs/wp-includes/class-wp-hook.php(334): WP_Hook->apply_filters()
#19 /var/www/xxx/htdocs/wp-includes/plugin.php(517): WP_Hook->do_action()
#20 /var/www/xxx/htdocs/wp-settings.php(427): do_action()
#21 /var/www/xxx/wp-config.php(101): require_once('...')
#22 /var/www/xxx/htdocs/wp-load.php(55): require_once('...')
#23 /var/www/xxx/htdocs/wp-admin/admin.php(34): require_once('...')
#24 /var/www/xxx/htdocs/wp-admin/site-editor.php(12): require_once('...')
#25 {main}
  thrown in /var/www/xxx/htdocs/wp-includes/pluggable.php on line 929
[06-Nov-2023 16:32:03 UTC] PHP Fatal error:  Uncaught Error: Undefined constant "SECURE_AUTH_COOKIE" in /var/www/xxx/htdocs/wp-includes/pluggable.php:929
Stack trace:
#0 /var/www/xxx/htdocs/wp-includes/pluggable.php(694): wp_parse_auth_cookie()
#1 /var/www/xxx/htdocs/wp-includes/class-wp-hook.php(310): wp_validate_auth_cookie()
#2 /var/www/xxx/htdocs/wp-includes/plugin.php(205): WP_Hook->apply_filters()
#3 /var/www/xxx/htdocs/wp-includes/user.php(3622): apply_filters()
#4 /var/www/xxx/htdocs/wp-includes/pluggable.php(70): _wp_get_current_user()
#5 /var/www/xxx/htdocs/wp-includes/l10n.php(98): wp_get_current_user()
#6 /var/www/xxx/htdocs/wp-includes/l10n.php(152): get_user_locale()
#7 /var/www/xxx/htdocs/wp-includes/l10n.php(894): determine_locale()
#8 /var/www/xxx/htdocs/wp-includes/class-wp-fatal-error-handler.php(47): load_default_textdomain()
#9 [internal function]: WP_Fatal_Error_Handler->handle()
#10 {main}
  thrown in /var/www/xxx/htdocs/wp-includes/pluggable.php on line 929

This happens when both WP Multi Network and Prime Mover are activated and only with the latest Prime Mover version 1.9.2

Disabling either one of these plugins will fix the error but since we’ve been using WP Multi Network for many years, and need it to manage multiple networks on the same installation, we have no other choice than to disable Prime Mover.

Is this a known conflict? Any way to get the two plugins to play nice again?

Thanks for any advise and attention to this issue 🙂