需要帮助解决$ stmt-> close（）上的致命错误；

Question

我不知道发生了什么。它是第一次工作，但突然停止了。

创建一个注册和登录系统，确定。经过测试，运作良好。最初是意外错误，现在显示如下：

致命错误：未捕获错误：在C：\ xampp \ htdocs \ playing \ index.php：91中的bool上调用成员函数close（）堆栈跟踪：＃0 {main}抛出在C：\ xampp \ htdocs中第91行的\ playing \ index.php

<?php // Initialize the session
session_start();

// Check if the user is already logged in, if yes then redirect him to welcome page
if(isset($_SESSION["loggedin"]) && $_SESSION["loggedin"] === true){
header("location: welcome.php");
exit;
}

// Include config file
require_once "common/server.php";

// Define variables and initialize with empty values
$Email = $Password = "";
$email_err = $password_err = "";

// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){

    // Check if Email is empty
    if(empty(trim($_POST["Email"]))){
        $email_err = "Please enter Email.";
    } else{
        $Email = trim($_POST["Email"]);
    }

    // Check if Password is empty
    if(empty(trim($_POST["password"]))){
        $password_err = "Please enter your Password.";
    } else{
        $Password = trim($_POST["password"]);
    }

    // Validate credentials
    if(empty($email_err) && empty($password_err)){
        // Prepare a select statement
        $sql = "SELECT id, Email, Password, Gender FROM users WHERE Email = ?";

        if($stmt = $conn->prepare($sql)){
            // Bind variables to the prepared statement as parameters
            $stmt->bind_param("s", $param_Email);

            // Set parameters
            $param_Email = $Email;

            // Attempt to execute the prepared statement
            if($stmt->execute()){
                // Store result
                $stmt->store_result();

                // Check if Email exists, if yes then verify Password
                if($stmt->num_rows == 1){                    
                    // Bind result variables
                    $stmt->bind_result($id, $Email, $hashed_password, $Gender);
                    if($stmt->fetch()){
                        if(password_verify($Password, $hashed_password)){
                            // Password is correct, so start a new session
                            session_start();

                            // Store data in session variables
                            $_SESSION["loggedin"] = true;
                            $_SESSION["id"] = $id;
                            $_SESSION["Email"] = $Email;                            

                            if ($Gender=="Male") {
                                header ("location: assets/step/Step1_Male.php");
                            } else {
                                echo "Female";
                            }

                            // Redirect user to welcome page
                            //header("location: success.html");
                        } else{
                            // Display an error message if Password is not valid
                            $password_err = "The Password you entered was not valid.";
                        }
                    }
                } else{
                    // Display an error message if Email doesn't exist
                   echo "No account found with that Email.";
                }
            } else{
                echo "Oops! Something went wrong. Please try again later.";
            }

        }

        // Close statement
        $stmt->close(); 
    }


    // Close connection
    $conn->close();
}
?>

'''