SANGO テーマをオンにした状態で Query Monitor プラグインをオンにすると下記のメッセージが表示されて操作不能になります。 Query Monitor プラグインがオンの状態で SANGO テーマに切り替えても同様です。 可能であればご対応いただけると幸いです。

Fatal error: Uncaught Error: Class "YahnisElsts\PluginUpdateChecker\v5p0\DebugBar\Panel" not found
in /home/sti-staging/www/dev-tech-lab.staging-test.sios.jp/wp-content/themes/sango-theme/vendor/yahnis-elsts/plugin-update-checker/Puc/v5p0/DebugBar/ThemePanel.php on line 9

Call stack:

include()
wp-content/themes/sango-theme/vendor/yahnis-elsts/plugin-update-checker/Puc/v5p0/Autoloader.php:80
YahnisElsts\P\v\Autoloader::autoload()
wp-content/themes/sango-theme/vendor/yahnis-elsts/plugin-update-checker/Puc/v5p0/DebugBar/Extension.php:40
YahnisElsts\P\v\D\Extension::addDebugBarPanel()
wp-includes/class-wp-hook.php:324
WP_Hook::apply_filters()
wp-includes/plugin.php:205
apply_filters()
wp-content/plugins/query-monitor/classes/debug_bar.php:53
Debug_Bar::init_panels()
wp-content/plugins/query-monitor/classes/debug_bar.php:18
Debug_Bar::__construct()
wp-content/plugins/query-monitor/collectors/debug_bar.php:77
register_qm_collectors_debug_bar()
wp-includes/class-wp-hook.php:324
WP_Hook::apply_filters()
wp-includes/class-wp-hook.php:348
WP_Hook::do_action()
wp-includes/plugin.php:517
do_action()
wp-settings.php:695
require_once()
wp-config.php:97
require_once()
wp-load.php:50
require_once()
wp-admin/admin.php:34
require_once()
wp-admin/index.php:10