Enabling USPS Causes Checkout Error
I have a Power Store. When I enable the USPS shipping, the user is getting an error:
Transaction Not Completed
We're sorry. Your transaction could not be completed. Either your credit card information or billing address has problems and cannot be processed
Please return to checkout and try again.
When I do not enable this, the checkout works fine. Apparently there is an authentication error with USPS's API. Can you help me please? Attached are the credentials you will need.