Trouble submitting to Mysql Database with a form, using php

Question

I keep getting an error "Unknown column 'test7a' in 'field list' ". I want my form to submit to my DB. The "test7a" is what I typed into my form. Below is my code: My form:

    <form action="core/testinsertcode.php" method="post" />
<p>First Name: <input type="text" name="FirstName" /></p>
<input type="submit"  value="Submit" />
</form>

My PHP:

<?php
error_reporting( E_ALL & ~E_NOTICE);
session_start();

require_once 'config.php';

// Create connection
$conn = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);


// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}
echo "Connected successfully";

$value = $_POST['FirstName'];

mysqli_query($conn, "INSERT INTO Form (FirstName)
VALUES ('$value')") or die(mysqli_error($conn));

mysqli_close($conn);

?>