PHP file not recognizing data sent from ajax file

I am attempting to create an ajax call to my php file to insert data. The issue I am running into is the data I send over is not being recognized.

The variables you will see in the php file is what is not being recognized:

$home_comment = $_POST['home_comment'];
    $username = $user->data()->username;

I am running an ini file that has the connection $con within it and it always has the $user variable.

Does anyone see what I am doing wrong?

<form action="" method="POST" id="comment-form">
            <label for="comment">Comment</label>
            <textarea cols="15" id="home-comment" name="comment" placeholder="Message" rows="5" maxlength="1000" required></textarea><br>
            <input type="hidden" name="token" value="<?php echo Token::generate(); ?>">
            <input id="comment-button" name="submit" type="submit" value="Post">
        </form>

Ajax:

$("#comment-form").on("submit", function (event) {
        //event.preventDefault();

        var home_comment = $("#home_comment").val();

        $.ajax({ 
            url: "comment-send.php", 
            type: "POST",
            data: {
                "home_comment": home_comment
            },
            success: function (data) {
            //  console.log(data); // data object will return the response when status code is 200
                if (data == "Error!") {
                    alert("Unable to post comment!");
                    alert(data);
                } else {
                    /*$("#newsletter-form")[0].reset();
                    $('.newsletter-popup').fadeIn(350).delay(2000).fadeOut();*/
                }
            },
            error: function (xhr, textStatus, errorThrown) {
                alert(textStatus + " | " + errorThrown);
                //console.log("error"); //otherwise error if status code is other than 200.
            }
        });
    });

PHP file:

$home_comment = $_POST['home_comment'];
$username = $user->data()->username;
$okay = true;

if ( $okay ) { 

    $comment_insert = "
        INSERT INTO home_comments 
        (id, user_id, username, comment)
        VALUES(?, ?, ?, ?)
        ";
    $comment_stmt = $con->prepare($comment_insert);
    $comment_stmt->execute(array('', $user_id, $username, $home_comment));
    }