Trouble with Checkout

-- url of the page with the problem -- : mafiaoutdoors.com
-- HikaShop version -- : 4.0.1
-- Joomla version -- : 3.8.11
-- PHP version -- : 7.1.18
-- Browser(s) name and version -- : Google Chrome

Hello,

My site is live at mafiaoutdoors.com. I have been using Hikashop Essentials for some time now and I seem to be having trouble with customers being able to check out properly. I would like to ask if you could look at my configuration and see if my checkout process can be simplified. I'm not sure if there is something that is not correct, but I get a lot of orders created, but many of them are not completed and paid.

I would like to share an admin login and have you check my process. I am using PayPal for my payment processor.

Thanks for any help you could offer.

I would add that I am willing to upgrade to Pro edition if that would help me be more efficient. I am losing sales due to the problems encountered with the checkout process.

After I put in the guest checkout email, I get the following warning:

Notice: Undefined index: shipping_address in /home/mafiaoutdoors/public_html/administrator/components/com_hikashop/classes/user.php on line 449.

What causes this?

I updated to 4.0.2 and now I can't access my configuration tab. I get the error: syntax error, unexpected ''*' (T_ENCAPSED_AND_WHITESPACE)