Albion's request for more tickets for Saturday's potential play-off clincher has been rejected by Nottingham Forest.
The Seagulls have sold out their allocation for the clash at the City Ground.
They requested more tickets after Forest's own play-off hopes were ended by Saturday's 4-1 defeat at Bournemouth but have been turned down.
Sky Sports will select the two Championship matches for live coverage on the final day after Wigan's visit to Birmingham tonight.
Albion have urged all season tickets to sign up for free for Seagulls Priority Gold Membership ahead of a possible home leg in the play-offs to help the club in the quick turnaround between matches.
Chief executive Paul Barber said: "We don't want to tempt fate, and I know fans won't want to either, but should we be successful at Nottingham Forest and other results go our way, it would help us enormously if fans would take the time between now and Saturday to sign up for Gold Membership.
"It's free of charge, and it is automatically cancelled at the end of the current season. No money will be take in the event we do not finish in the top six, but if we are successful tickets will be automatically processed, with no booking fee charged, and the game automatically uploaded to their cards."
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