Warning: mysqli_errno() expects parameter 1 to be mysqli, boolean given in /var/www/html/libraries/joomla/database/driver/mysqli.php on line 992

Warning: mysqli_error() expects parameter 1 to be mysqli, boolean given in /var/www/html/libraries/joomla/database/driver/mysqli.php on line 1004
Error: Could not connect to MySQL server.:
Warning: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: /var/lib/php/session) in /var/www/html/libraries/joomla/session/handler/native.php on line 194