Problem
I have tried printing a FedEx shipping label and am seeing following error returned:
Error: Package 1 - Special service SIGNATURE_OPTION is invalid. (PACKAGE_INDEX=1 SPECIAL_SERVICE_TYPE=SIGNATURE_OPTION)
Solution
This error is being returned because FedEx requires a different value for 'SignatureOptionType' Order Extended Property from what was currently submitted.
Please see list for available values and assign a different option:
Related articles:
Order Properties for FedEx integration