Your Unified Registry application, when you receive a “ Settlement Registration ” request with the <Documents> data block, must manage a retry policy to download the documentation associated with that settlement.
The recommendation from the AOC Consortium is to make the re-attempts spaced in time and that, once the maximum of previously stipulated re-attempts is exceeded, it should be re-attempted, as the source application may not have been integrated with the method of saving documentation (documents not retrievable by current web services, such as eFACT, despite returning the <Documents> data block).