PayPal orders dropping out

One of our clients is experiencing the issue where orders are being picked up by PayPal, but after completion, the order does not go back to Zen Cart.

I have seen on here that this is an issue from time to time when the PayPal server is down, however by all accounts occurs once in a blue moon.

She has had it occur now four times - and she does not have a huge volume of orders coming through.

Is there anywhere else we should be looking? Most orders come through ok.

thanks
URsh
webcare.com.au

Two options:

a) go through all these troubleshooting steps and figure out what is busted in your server setup: http://www.zen-cart.com/wiki/index.php/PayPal

or

b) switch to using PayPal Express Checkout which is much more reliable and not dependent on the communication weaknesses that the Website Payments Standard/IPN method uses.

But, you don't want both enabled at the same time. Just one or the other.

Thank you very much!