My customers are getting an error if they are trying to have their order shipped to a Canadian address. It will say during step 1 of checkout:
An error occurred with the USPS shipping calculations.
If you prefer to use USPS as your shipping method, please contact the store owner.

I think this may be the only country that is giving the error. How would I go about correcting this?

I am using v1.2.7

Thanks!