Because e-commerce involves so many moving parts, problems and incompatibilities can happen. The biggest source of frustration can be incorrect understanding or expectations with regard to your payment gateway. Please read the Payment Gateway Notes for critically important information regarding returning users, subscriptions, and limitations your gateway might be imposing on your transactions.

Internet Explorer (all versions through 8) have a limitation on the amount of data that they can accept in the URL (2,083 characters). Since you're passing information back and forth from your site to your FoxyCart cart every time a user adds something to the cart, this can create problems if you use very large forms.

If you are using large “add to cart” forms, you have a few options:

1. Do not use the standard cart in the modal window (from foxycart.complete.js, a la Colorbox). Instead, load the cart on a new window.
2. Attempt a workaround. More info on this forum thread.