VeriFLY and the separate online uploading tool (Salesforce) haven’t been working as they’re intended to for a quite a while now and are even more troublesome when it’s a connecting itinerary. Most of the time it still won’t let you check-in online despite completing everything which is frustrating. However I’d still recommend people to do this (particularly VeriFLY as the attestation is embedded within it) as it does save time at the airport regardless as they will see that the documents have been verified and in most instances you won’t need to produce the documents again at any point in the journey.