InvalidOperationException: Sequence contains no elements

System.Linq.Enumerable.First[TSource] (System.Collections.Generic.IEnumerable`1[T] source) (at <351e49e2a5bf4fd6beabb458ce2255f3>:0)

GridManager.GetHeroSpawnTile () (at Assets/Scripts/Managers/GridManager.cs:46)

UnitManager.SpawnHeroes () (at Assets/Scripts/Managers/UnitManager.cs:26)

GameManager.ChangeState (GameState newState) (at Assets/Scripts/Managers/GameManager.cs:34)

GridManager.GenerateGrid () (at Assets/Scripts/Managers/GridManager.cs:41)

GameManager.ChangeState (GameState newState) (at Assets/Scripts/Managers/GameManager.cs:31)

GameManager.Start () (at Assets/Scripts/Managers/GameManager.cs:21)


콘솔창에서 오류가 이런식으로 뜨면 뭐가 문제인건가요 ㅜㅜㅜ 이틀째 이것만 보고있어요 스크립트도 필요하면 올릴께요