php第一次插入数据成功后，再次插入就一直失败。

代码奉上

报错信息：数据插入失败，请重试

<?php
session_start();
header("Content-type:text/html;charset=utf-8");
//登陆数据库
$link = mysqli_connect('localhost','ClassCard','nMRZrC42wDjWHeAL','ClassCard');
if (!$link) {
 die("连接失败:".mysqli_connect_error());
}

$Name = $_POST['Name'];
$ID = $_POST['ID'];
$Phone = $_POST['Phone'];
//填写错误判定
if($Name == "" || $ID == "" || $Phone == "")
{
    echo ('以上三项不能为空！重新填写');
}
//重复注册判定
$sql="select*from UserST WHERE Name = '$Name' AND ID = '$ID'";
$result=mysqli_query($link,$sql);
$row=mysqli_fetch_assoc($result);
$PassName = $row["Name"];
$PassId = $row["ID"];
if($Name == "$PassName" && $ID == "$PassId")
{
    echo "该用户已注册，请勿重复注册";
}
//执行写入操作
else
{
    date_default_timezone_set('prc');
    $RegisterTime = date('Y-m-d',time());
    $sql = "INSERT INTO UserST VALUES ('$ID', '$Name', '', '0', '新开', '$RegisterTime', '$Phone')";
    if(!(mysqli_query($link,$sql)))
    {
        echo ('数据插入失败，请重试');
    }
    else
    {
        echo ('录入成功！');
    }
mysqli_close($link);
}
?>

https://blog.csdn.net/tammy1151/article/details/73087293