$servername = "myusername-projectname-somenumber";
$port = 3306;
$username = "form";
$password = "password";
$dbname = "dbname";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname, 3306);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

SHOW VARIABLES WHERE Variable_name = 'hostname';

Connection failed: Unknown MySQL server host 'myusername-projectname-somenumber' (0)