Connect Error(2002)Connection refused (Heroku) - php

Question

I have been trying to connect to my database (I used Xampp) and made a PHP trying to link the file to the "users" database that I made. There is an issue as whenever I click the "Register" button it has an error saying "Connect Error(2002)Connection refused." Any help would be appreciated!
PHP code
<?php
$name = $_POST['name'];
$username = $_POST['username'];
$password = $_POST['password'];
$email = $_POST['email'];
$phone = $_POST['phone'];
if (!empty($name) || !empty($username) || !empty($password) || !empty($email) || !empty($phone)) {
$host = "localhost:80";
$dbUsername = "root";
$dbPassword = "";
$dbname = "pracdata";
//create connection
$conn = new mysqli($host, $dbUsername, $dbPassword, $dbname);
if (mysqli_connect_error()) {
die('Connect Error('. mysqli_connect_errno().')'. mysqli_connect_error());
} else {
$SELECT = "SELECT email From users Where email = ? Limit 1";
$INSERT = "INSERT Into users (name, username, password, email, phone) values(?, ?, ?, ?)";
//Prepare statement
$stmt = $conn->prepare($SELECT);
$stmt->bind_param("s", $email);
$stmt->execute();
$stmt->bind_result($email);
$stmt->store_result();
$rnum = $stmt->num_rows;
if ($rnum==0) {
$stmt->close();
$stmt = $conn->prepare($INSERT);
$stmt->bind_param("ssssii", $username, $username, $password, $email, $phone);
$stmt->execute();
echo "Your account has been registered!";
} else {
echo "This email is already linked to Preak account";
}
$stmt->close();
$conn->close();
}
} else {
echo "All fields are required";
die();
}
?>