Sold Items suddenly Not Updating and No Order Emails?

Hi all,
I am having trouble with my site today. I just listed new items for sale, and they are selling out. I know this because I am receiving the Paypal payments, and I can go to "who's online" in zen cart to see customers that have checked out. However, I have no pending orders, no new orders, no email order summary, nothing. I have had to reply to the Paypal emails to ask customers which items they purchased so I can manually update that they sold out.

Can you help with this?

You have problems because PayPal's server is unable to talk to your server to trigger storing the order. That's a limitation of the Website Payments Standard module. Use Express Checkout instead:

1. Admin->Modules->Payment->PayPal Website Payments Standard --- click "REMOVE"
2. Admin->Modules->Payment->PayPal Express Checkout -- click "Install"
3. Configure the module. reference: https://www.zen-cart.com/getpaypal

Thanks for the tip.

I am wondering though why do I need to change settings when they have been working fine for the past three years? This seems to have just started today. I am using version 1.3.6. and have not upgraded yet. my site is https://www.kabsconcepts.com

edited to add: I just double checked my settings. I went to modules>payments> and I am set up with Paypal IPN

If the problem "just started", then it could be a result of any of the following:
a) you've been hacked http://www.zen-cart.com/wiki/index.php/Recovering_From_Hacks
b) you or someone with access to your site has changed something
c) your hosting company has changed firewall configurations or external-php-communication configurations on the server
d) your PayPal account has had its IPN Notification feature disabled because of numerous failures http://www.zen-cart.com/wiki/index.php/PayPal

By the way, your version of Zen Cart is very old. You should plan on upgrading soon.

Thanks again for the tips! I will see if I can figure out what is up.

As for upgrading, I have an email into my web designer to see if she can do the upgrade. I am wondering though if it is something I can do myself? Is it pretty straight forward? Do you need a lot of coding knowledge to do it? I am worried I would completely mess up what I already have!!