Help, got fatal error

Hello, I went to enable all branding options and the site collapsed and gave me the following error.

What should I do?

Fatal error: Uncaught Error: Call to a member function get() on null in /var/www/html/wp-includes/query.php:28 Stack trace: #0 /var/www/html/wp-content/plugins/booked/includes/profiles.php(42): get_query_var('profile') #1 /var/www/html/wp-includes/plugin.php(235): booked_profiles->display_profile_markup('<p>You can chan...') #2 /var/www/html/wp-content/plugins/ultimate-branding/ultimate-branding-files/modules/admin-help-content.php(101): apply_filters('the_content', '<p>You can chan...') #3 /var/www/html/wp-content/plugins/ultimate-branding/ultimate-branding-files/modules/admin-help-content.php(71): ub_Ahc_AdminHelpContent->_initialize_help_content() #4 /var/www/html/wp-content/plugins/ultimate-branding/ultimate-branding-files/modules/admin-help-content.php(338): ub_Ahc_AdminHelpContent->__construct() #5 /var/www/html/wp-content/plugins/ultimate-branding/ultimate-branding-files/includes/functions.php(127): include_once('/var/www/html/w...') #6 /var/www/html/wp-content/plugins/ultimate-branding/ultimate-branding-files/clas in /var/www/html/wp-includes/query.php on line 28