Add to Cart Is Broken in My Preview

If Add to Cart isn't working, it may not be an error from the optimization. The preview could be redirecting you back to your live store.

To check for this, check the URL after clicking Add to Cart. If you're no longer on the preview site, the add to cart has redirected you. This won't be a problem after publishing changes since you'll no longer be using the preview link.

If other site functionality that was previously working stopped in your preview, it's probably the Minify JS option. Disabling that should get that working again!