As the organizer, you control the ability to share the game code with all potential players, therefore inactive players and active players both count towards the total number of players for your subscription. 


If your inactive players are for a prior event, you can reset the game for your new event. Resetting the game will place the number of players back to zero and remove both your currently active and inactive players. 


If you wish to keep your active players, you would have to upgrade your subscription to increase the number of players for your game.