Fatal error: Uncaught Error: Call to a member function using_index_permalinks() on null in /var/www/html/wp-includes/rest-api.php:516 Stack trace: #0 /var/www/html/wp-includes/rest-api.php(579): get_rest_url(NULL, '/', 'rest') #1 /var/www/html/wp-content/plugins/bergsy-wp-api/bergsy-wp-api.php(33): rest_url() #2 /var/www/html/wp-includes/class-wp-hook.php(341): bergsy_wp_api_init('') #3 /var/www/html/wp-includes/class-wp-hook.php(365): WP_Hook->apply_filters(NULL, Array) #4 /var/www/html/wp-includes/plugin.php(522): WP_Hook->do_action(Array) #5 /var/www/html/wp-settings.php(593): do_action('plugins_loaded') #6 /var/www/html/wp-config.php(116): require_once('/var/www/html/w...') #7 /var/www/html/wp-load.php(50): require_once('/var/www/html/w...') #8 /var/www/html/wp-blog-header.php(13): require_once('/var/www/html/w...') #9 /var/www/html/index.php(17): require('/var/www/html/w...') #10 {main} thrown in /var/www/html/wp-includes/rest-api.php on line 516