PHP和MYSQL代码在localhost中不起作用

Question

Good day. I would like to ask what's wrong with my codes. These already worked in a website that we made with my mate but as I run "register.php", I cannot insert data to my table named 'accounts'. Thanks in advance. Here are the codes:

connect.php

<?php 
//Callback function for connecting the website to the accounts database.
$connect = mysqli_connect('localhost', 'root', '');
if (!$connect){
    die("Database Connection Failed" . mysqli_error($connect));
}
//Selects the database
$select_database = mysqli_select_db($connect, 'users');
if (!$select_database){
    die("Database Selection Failed" . mysqli_error($connect));
}

register.php

<?php
session_start();
require('connect.php');
//If the values are posted, insert them into the database.
if (isset($_POST['username']) && isset($_POST['pass'])){
    $username = $_POST['username'];
    $email = $_POST['email'];
    $password = $_POST['pass'];
    $passwordauth = $_POST['passwordauth'];
    if($password == $passwordauth){
    $password = hash ( 'sha256' , $password ); // hash function creates
        an encrypted code form the $password for security considerations
    $query = "INSERT INTO accounts (username, password, email) VALUES
           ('$username', '$password', '$email')";
    $result = mysqli_query($connect, $query);
    if($result){
        $msg = "User Created Successfully.";
    }
    else{
        $msg ="User Registration Failed";
    }
    }
    else
    {
    $msg ="Password does not match.";
    }
}