Reply To: USPS not listed in E-shipping extensions

[vinny]

As long as you have the credentials from USPS, you should be ready to go. Just give them the call to go live.

The sandbox environment is used automatically when eShop is in Test mode. However, due to an error on USPS’ side, we use live mode even when eShop is in Test mode – believe it or not, USPS’ test servers don’t support RateV4.