406响应与$.post请求jQuery到外部PHP

$('.save').click(function() {
    $.post('store.php', $('.formss').serialize())
});

store.php

<?php
$tts = $_POST['tts'];
$texttostore = $tts;
$servername = "localhost";
$username = "xxx";
$password = "xxx";
$dbname = "notes";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 
$sql = "INSERT INTO notes (code)
VALUES ('$texttostore')";
if ($conn->query($sql) === TRUE) {
    echo stripslashes(str_replace(''r'n',PHP_EOL,$texttostore));
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}
$conn->close();
?>

. htaccess

<IfModule mod_security.c>
SecFilterCheckURLEncoding Off
</IfModule>

得到以下响应:https://i.stack.imgur.com/MUZpX.png

我也尝试过本地表单提交，但它也会带来一个错误的请求。

注意:存储时保留所有空白和格式，这是有意的

如果有人能帮我，那就太好了，谢谢:)