"You have chosen to provide carton content information via the Amazon Marketplace Web Services feed API. Please upload box content information via _POST_FBA_INBOUND_KARTON_CONTENTS_. If you prefer to specify the carton contents information in SellerCentral, set a value other than FEED for IntendedBoxContentsSource."
This error message means that the carton information could not be successfully submitted through the API interface.
Delete or archive the FBA Send-Ins (which was not successful) in VentoryOne and retry the FBA submission.