Form does not go to action page on submit - php

Question

Edit 2: I traced the code through the php, and realized that it was a faulty header that was causing it to bounce back. I've fixed the header and now the form behaves as it should. Thanks everyone for your help.
EDIT: I noticed the form is quickly refreshing when I submit, so I think it is going to the action page (createlist.php) and immediately bouncing back, so there must be some issue there. Here is the code for createlist.php:
<?php
if (!isset($_SESSION)) {
session_start();
}
if (!defined(__DIR__)) {
define(__DIR__, dirname(__FILE__));
}
require_once(__DIR__.'/../config.php');
//Connect to server and select database.
$link = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_DATABASE) or die('Cannot connect to server');
//mysql_select_db(DB_DATABASE) or die('Cannot select database');
$tbl_name = 'lists'; //Table name
//Retreive data from form
$listname = $_POST['listName'];
$admin_id = $_SESSION['SESS_MEMBER_ID'];
$listtype = 'list';
//Create listname session variable for catinit.php
$_SESSION['listname'] = $listname;
//Insert new row
$sql = "INSERT INTO $tbl_name(admin_id, listname, listtype) VALUES ('$admin_id', '$listname', '$listtype')";
$result = mysqli_query($link, $sql);
if ($result) {
header("location: catinit.php");
} else {
die("Could not create list");
}
//mysql_close();
?>
I have 2 forms on a page, and while it was working before, since adding the backend handling of the information it has broken. Now when I submit either of the forms on the page nothing happens, it does not even attempt to load the action pages. I am completely lost as to what is stopping it from submitting, as everything looks like its working.
<h1>Create a New List</h1>
<form action = "createlist.php" method = "POST" id = "formId" onsubmit = "formValidate(0, 0, 0, 1, 'formId', 'submitError', event)">
<p>List Name:
<input type = "text" id = "listName" name = "listName" placeholder = "New List" onblur = "listNameValidate('listName','errorName1')" required><span class = "error" id = "errorName1"></span></p>
</form>
<h2>Categories</h2>
<ul class = "catList" id = "list">
<table>
<?php
$cats = array('Produce', 'Meat/Dairy', 'Baked Goods', 'Dry/Canned Goods', 'Household Items');
//Check to see if Session version of array has different values
if (isset($_SESSION['catArray']) && $_SESSION['catArray'] != $cats) {
$cats = $_SESSION['catArray'];
} else {
$_SESSION['catArray'] = $cats;
}
foreach ($cats as $cat) {
$index = array_search($cat, $cats);
echo '<tr><td><li>'.$cat.'</li></td><td> Remove</td></tr>';
}
?>
</table>
</ul>
New Category: <br>
<form action = "addcat.php" method = "POST" id = "addcat">
<input type = "text" id = "newCategory" name = "newCat" placeholder = "Category name" onblur = "listNameValidate('newCategory','errorName2')">
<input type = "hidden" name = "catArray" value = "<?php echo htmlentities(serialize($cats)); ?>" >
<input type = "submit" value= "Add" class = "add"><span class = "error" id = "errorName2"></span>
</form>
<h2>Invite Members</h2>
Add a new Member: <br>
<input type = "email" id = "email" name = "Email" placeholder = "Email Address" onblur = "emailValidate('email', 'errorEmail')">
<input type = "button" value = "Add" class = "add" ><span class = "error" id = "errorEmail"></span>
<p><input type = "submit" form = "formId" value = "Create"></p>
<p class = "submitError" id = "submitError"></p>