尝试访问localhost mysql数据库时出现500错误

I have a small page that I'm trying to building a journal with using PHP and My_SQL for both practice and recreation. I have a solid understanding of PHP but less so on My_SQL. Based on what I viewed it seemed that I can implement it almost like looking up a function and applying data to the corresponding areas. I tried doing the most basic thing and connect to my localhost server, but I cannot figure out why I am getting a 500 error. What is wrong with my server???

$servername = "http://127.0.0.1/";
 $username = "root";
 $password = "***";

// Create connection
$conn = new mysqli($servername, $username, $password);

// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
} 
else echo "Connected successfully";

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