When using FedEx SmartPost services, you might come across the "8670 ERROR - Invalid Smart Post Hub Id. 2505 NOTE "USPS_DELIVERY_CONFIRMATION" was added to the smart post special services." error.
This issue occurs because your FedEx account has not been set up on FedEx's end to be able to use SmartPost services. To utilize SmartPost, your account should be a Production account, enabled for Smartpost and assigned to a HubID.
Contact your FedEx point of contact and request to set your account accordingly.
Once ready, if your setup is in place on techSHIP's end, retry.
If you're not sure you have set up Smarpost properly on your techSHIP Billing Accounts, make sure you review the following articles as well: