Limiting shipping areas

I want to limit where I can ship a large item. I tried to follow the instruction found on this page by user yukikatayama.

https://wordpress.org/support/topic/woocommerce-limiting-areas-an-item-is-shipped-to/

I have two shipping zones. The first one is a zip-code base (1). The second is a state-based (2). Then I have two classes (A) and (B). In (1) the flat rate is 0 for (A) and N/A for (B). In the state zone I have a flat rate N/A for (A) and 0 for (B). When I go the add to the cart and enter a zip code outside zone (1) it shows the (B) rate. But when I check out it says there is a problem with the item and to go back and fix it. However, it does not state what is wrong.

The page I need help with: [log in to see the link]