Fatal error: Uncaught Error: Call to undefined function is_blog_installed() in /home/lincost/domains/lincost.pl/public_html/wp-includes/load.php:540 Stack trace: #0 /home/lincost/domains/lincost.pl/public_html/wp-settings.php(140): wp_not_installed() #1 /home/lincost/domains/lincost.pl/public_html/wp-config.php(48): require_once('/home/lincost/d...') #2 /home/lincost/domains/lincost.pl/public_html/wp-load.php(37): require_once('/home/lincost/d...') #3 /home/lincost/domains/lincost.pl/public_html/wp-blog-header.php(13): require_once('/home/lincost/d...') #4 /home/lincost/domains/lincost.pl/public_html/index.php(17): require('/home/lincost/d...') #5 {main} thrown in /home/lincost/domains/lincost.pl/public_html/wp-includes/load.php on line 540

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'wp_ob_end_flush_all' not found or invalid function name in /home/lincost/domains/lincost.pl/public_html/wp-includes/class-wp-hook.php on line 286