Customers can't check out due to a postal code origin error
There is no origin because in your System > Configuration > Site Information tab there is no zip code for the shipments to originate from. This prevents shipping rates from being calculated.
Please add in a zip code on the > Site Information tab, and save your changes. Please confirm that the zip code was actually saved and do a test on the frontend to confirm the issue has been resolved.
Note: This error will only occur if the customer is using UPS and/or Fedex as their only shipping options.