Fatal error: Uncaught Error: Class "OCA\Theming\Themes\DefaultTheme" not found in /var/www/html/nextcloud/apps/theming/lib/Themes/HighContrastTheme.php:12 Stack trace: #0 {main} thrown in /var/www/html/nextcloud/apps/theming/lib/Themes/HighContrastTheme.php on line 12