I just installed the USPS shipping module, registered my site with USPS Web Tool Registration, and received test username and password.
I tried to test it but get this error every time during checkout.
United States Postal Service An error occured with the USPS shipping calculations.
If you prefer to use USPS as your shipping method, please contact the store owner.
My site is hosted through Bluehost and I am using osCommerce version 2.3.1 (Stable).
I have the paypal payment setup and testing with the sandbox server.
Can anyone please help me?