Warning: mysqli_connect(): php_network_getaddresses: getaddrinfo failed: Name or service not known in /var/www/html/suggestion_box_config.php on line 8

Warning: mysqli_connect(): (HY000/2002): php_network_getaddresses: getaddrinfo failed: Name or service not known in /var/www/html/suggestion_box_config.php on line 8

Fatal error: Uncaught Error: Call to undefined function mysql_error() in /var/www/html/suggestion_box_config.php:8
Stack trace:
#0 /var/www/html/lib/contents/suggestion_box_view.inc.php(2): include()
#1 /var/www/html/index.php(104): include('/var/www/html/l...')
#2 {main}
  thrown in /var/www/html/suggestion_box_config.php on line 8