The way Seatfrog auctions work is that we are initially allocated several seats to offer as First Class upgrades. But as people return to travel and with social distancing still in place, services can quickly become busier than expected. When this happens, availability is reduced, and we may not be able issue an upgrade.
While we continue to provide hundreds of upgrades each day, Seatfrog upgrades are last-minute and can't be guaranteed. When the auction closes or a sale is reached, we check with the train operator and their reservation system to ensure there is availability. If there is, we'll immediately grant an upgrade and a new seat reservation. But when we're unable to confirm a reservation, the auction will close with 'All Seats Sold Out' or 'No Upgrades Available" depending on your device. This means that the initial allocation of seats are no longer available to Seatfrog.