我的登录系统出现解析错误

Question

由于某种原因，当我按照教程进行操作时，它给我一个错误

我是PHP的新手，所以我一直在看PHP教程系列。当涉及到登录系统时，出现错误。请注意，我还有另一个php脚本将它连接到我的数据库中，但该脚本似乎运行良好。

Parse error: syntax error, unexpected 'else' (T_ELSE)

这是我的php：

<?php

    if (isset($_POST['login-submit'])) {
        require 'connection.php';

        $mailuid = $_POST['mailuid'];
        $password = $_POST['pwd'];
        if (!mysqli_stmt_prepare($stmt, $sql)) {
                header("Location: ./user-login.php?error=sql");
                exit();
            if (empty($mailuid) || empty($password)) {
                header("Location: ../user-login.php?error=emptyfields");
                exit();
            } else {
                $sql = "SELECT * FROM users WHERE uidUsers=? OR emailUsers=?;";
                $stmt = mysqli_stmt_init($conn);

                } else {

                    mysqli_stmt_bind_param($stmt, "ss", $mailuid, $mailuid);
                    mysqli_stmt_execute($stmt);
                    $result = mysqli_stmt_get_result($stmt);
                    if ($row = mysqli_fetch_assoc($result)) {
                        $pwdCheck = password_verify($password, $row['pwdUsers']);
                        if ($pwdCheck == false){
                            header("Location: ./user-login.php?error=pwdincorrect");
                            exit();
                        } else if ($pwdCheck == true) {
                            session_start();
                            $_SESSION['userId'] = $row['idUsers'];
                            $_SESSION['userIid'] = $row['uidUsers'];

                            header("Location: ./user-index.php?login=success");
                            exit();
                        } else {
                            header("Location: ./user-login.php?error=pwdincorrect");
                            exit();
                        }   

                    } else {
                        header("Location: ./user-login.php?error=nouser");
                        exit();
                }

            }
        }


    } else {
        header('Location: ./user-login');
        exit();
    }

这是我的登录表格。

<?php
include('header.php');
?>
<br>

<div id="register-heading2">
    <h1>Register</h1>

</div>
<div id="register-form-container">
    <form action="login.php" method="POST">
        <label id="register-lable">Username or Email:</label>
        <input id="register-input" type="text" name="mailuid" placeholder="Username or Email">
        <br>
        <label id="register-lable">Password:</label>
        <input id="register-input" type="password" name="pwd" placeholder="Password">
        <br>
        <button class="ghost2" name="login-submit" type="submit" >Log in</button>
    </form>
</div>