为什么我的if（$ row = mysqli_fetch_assoc（$ result））没有越过第一行？

Question

我正在尝试制作一个登录系统，并且代码似乎在与assoc有关的if语句的开始处停止。
我尝试更改输入的参数，但似乎无济于事。

<?php
$value1 = $_POST['uname'];
$value2 = $_POST['pwd'];
if (isset($_POST['loginbtn'])) {
    //completes all of the code, only if the login button has been pressed
    require 'creationlink.php';
    //connects to database
    if (empty($value1) || empty($value2)) {
        header("Location: index.php?error=emptyfields");
        exit();
    }
    //checks no fields are blank
    else {
        $sql  = "SELECT * FROM loginTable WHERE username=?;";
        $stmt = mysqli_stmt_init($conn);
        if (!mysqli_stmt_prepare($stmt, $sql)) {
            header("Location: index.php?error=sqlerror");
            exit();
        } else {
            mysqli_stmt_bind_param($stmt, "ss", $value1, $value1);
            mysqli_stmt_execute($stmt);
            $result = mysqli_stmt_get_result($stmt);
            if ($row = mysqli_fetch_assoc($result)) {
                $pwdcheck = password_verify($value2, $row['password']);
                if ($pwdcheck == false) {
                    header("Location: index.php?error=wrongpassword");
                    exit();
                } else if ($pwdcheck == true) {
                    session_start();
                    $_SESSION['userID']   = $row['loginID'];
                    $_SESSION['username'] = $row['username'];
                    header("Location: index.php?error=success");
                    exit();
                } else {
                    header("Location: index.php?error=wrongpassword");
                    exit();
                }
            } else {
                header("Location: index.php?error=nouser");
                exit();
            }
        }
    }
    mysqli_stmt_close($stmt);
    mysqli_close($conn);
    //closes connection
} else {
    header("Location: index.php?error=nonononono");
    exit();
}
?>

我希望该程序允许用户登录（如果他们具有正确的详细信息）。
该程序应返回首页，并在URL中显示成功消息