Warning: mysqli_connect(): php_network_getaddresses: getaddrinfo failed: Name or service not known in /var/www/html/db_init.php on line 21

Warning: mysqli_connect(): (HY000/2002): php_network_getaddresses: getaddrinfo failed: Name or service not known in /var/www/html/db_init.php on line 21
Could not connect
Warning: mysqli_set_charset() expects parameter 1 to be mysqli, boolean given in /var/www/html/db_init.php on line 27
Could not connect
Warning: mysqli_select_db() expects parameter 1 to be mysqli, boolean given in /var/www/html/db_init.php on line 31
Could not connect
Warning: mysqli_prepare() expects parameter 1 to be mysqli, boolean given in /var/www/html/db_init.php on line 38

Fatal error: Call to a member function execute() on null in /var/www/html/db_init.php on line 46