Fatal error: Uncaught TypeError: WP_Translation_Controller::set_locale(): Argument #1 ($locale) must be of type string, null given, called in /home/gstudies/public_html/wp-includes/l10n.php on line 803 and defined in /home/gstudies/public_html/wp-includes/l10n/class-wp-translation-controller.php:87 Stack trace: #0 /home/gstudies/public_html/wp-includes/l10n.php(803): WP_Translation_Controller->set_locale() #1 /home/gstudies/public_html/wp-includes/l10n.php(1391): load_textdomain() #2 /home/gstudies/public_html/wp-includes/l10n.php(1408): _load_textdomain_just_in_time() #3 /home/gstudies/public_html/wp-includes/l10n.php(194): get_translations_for_domain() #4 /home/gstudies/public_html/wp-includes/l10n.php(339): translate() #5 /home/gstudies/public_html/wp-content/plugins/bt_cost_calculator/bt_cost_calculator.php(1177): esc_html__() #6 /home/gstudies/public_html/wp-includes/class-wp-hook.php(324): bt_quote_map_sc() #7 /home/gstudies/public_html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters() #8 /home/gstudies/public_html/wp-includes/plugin.php(517): WP_Hook->do_action() #9 /home/gstudies/public_html/wp-settings.php(559): do_action() #10 /home/gstudies/public_html/wp-config.php(77): require_once('/home/gstudies/...') #11 /home/gstudies/public_html/wp-load.php(50): require_once('/home/gstudies/...') #12 /home/gstudies/public_html/wp-blog-header.php(13): require_once('/home/gstudies/...') #13 /home/gstudies/public_html/index.php(17): require('/home/gstudies/...') #14 {main} thrown in /home/gstudies/public_html/wp-includes/l10n/class-wp-translation-controller.php on line 87

Fatal error: Uncaught TypeError: WP_Translation_Controller::set_locale(): Argument #1 ($locale) must be of type string, null given, called in /home/gstudies/public_html/wp-includes/l10n.php on line 803 and defined in /home/gstudies/public_html/wp-includes/l10n/class-wp-translation-controller.php:87 Stack trace: #0 /home/gstudies/public_html/wp-includes/l10n.php(803): WP_Translation_Controller->set_locale() #1 /home/gstudies/public_html/wp-includes/l10n.php(959): load_textdomain() #2 /home/gstudies/public_html/wp-includes/class-wp-fatal-error-handler.php(49): load_default_textdomain() #3 [internal function]: WP_Fatal_Error_Handler->handle() #4 {main} thrown in /home/gstudies/public_html/wp-includes/l10n/class-wp-translation-controller.php on line 87