Also, I sent a note to the USPS tech support asking them to resolve the error when using the secure URL. But, I don't understand the non-secure URL returning no errors and still not being able to complete the PS transaction because of a calculation issue calculating shipping.
Note: After thorough testing it appears that when 'Priority' mail is selected in the USPS Postal mailing options instead of 'First Class' the problem goes away and shipping is included in the checkout process. Is this the case?
Note: As for our cart status, we appear set to go using a USPS shipping rule, a 'US Postal Service' Provider, a 'United States' destination country, the USPS http://production.shippingapis.com/shippingapi.dll PRODUCTION URL, and the USPS Delivery type 'Priority' mail.
Question: What happens if someone needs international mailing to another country? Can I use more than one shipping rule?