We are now able to obtain USPS Cubic rate and shipping labels. The following issue as been resolved by USPS.
Description of earlier issue:
We are unable to obtain USPS Cubic rate and shipping label due to an issue on USPS side. We are waiting for a fix from USPS. This issue mostly affects orders > 1LB, and won't impact shipping labels generation for lower than 1LB packages.
We are actively working with USPS to resolve this. If you need to ship out packages urgently and are blocked by this issue, we recommend to use UPS Ground or Ground Saver services as a temporary workaround.
Teapplix now provides discounted DAP rate for UPS Ground and Ground Saver. If you don't own a UPS account, you may setup a Teapplix provided UPS account on the Integration->Carrier page.
Please contact our support if you have any questions or issues.