The error (Unable to Create Shipment: Notification no. 0 Severity: ERROR Code: 6070 Message: Unable to retrieve Letterhead and/or Signature images. Source: ship.) from FedEx typically occurs when the required letterhead or signature images are missing from the FedEx connection. To resolve this issue, review the steps below:
Upload your letterhead and signature images by following the FedEx Integration article.
If you encounter issues while uploading, refer to the Unable to Upload article for further guidance.
By following these steps, you should be able to resolve the error.