This can occur for two reasons:
- Not enough confirmed starters. Lightning Lineups requires enough confirmed starters in the player pool to generate fair lineups. If it's a small game slate, or too early in the day for starters to be confirmed you may see no lineups being generated. Or it may generate some lineups but then struggle to generate more. The closer to the scheduled start of games, the more lineups will be able to be generated.
- The sport is out of season or has no scheduled games.