Hi.
Warning message fixed. Update to version 1.2.1.
If the USPS API does not returns shipping methods, you will see the message: “There are no shipping methods available. Please double check your address, or contact us if you need any help.”
Possible reasons:
-Wrong or empty origin postcode (“postcode” in admin panel)
-Wrong destination postcode.
-Too much weight or dimensions of the goods.
Also, this plugin allows to calculate rates for domestic shipping only.