If you have set Great Balls to be thrown but you don’t have any, you can’t catch Pokémon. You’ll be able to catch Pokémon if you obtain Great Balls or select other types of Poké Ball that you do have (Poké Balls or Ultra Balls) to be thrown.
If you have set Great Balls to be thrown but you don’t have any, you can’t catch Pokémon. You’ll be able to catch Pokémon if you obtain Great Balls or select other types of Poké Ball that you do have (Poké Balls or Ultra Balls) to be thrown.