The NFL now says it knew last week there were problems with the installation of a temporary section at Cowboys Stadium, but they hoped until a few hours before the game that it would be ready.
"At the end, we just ran out of time," NFL executive vice president Eric Grubman said.
It wasn't, and over 400 angry fans were told their tickets would not be honored. They were forced to watch the game on monitors or use standing-room platforms in corners of Cowboys Stadium.
Another 850 fans were moved from their seats in the temporary sections to other seats.
"It was obviously a failure on our behalf, and we have to take responsibility for that," NFL Commissioner Roger Goodell said.
The fans who were turned away are being offered triple the face value of their tickets, and they're also receiving free tickets to next year's Super Bowl.
The Associated Press contributed to this story.