Pokémon Go: How to fix ‘The Gym is under attack! Try again later’ error

How do you fix the ‘The Gym is under attack! Try again later’ bug in Pokémon Go? By turning up the clock!Pokémon Go is currently experiencing a bug where the game incorrectly throws up an error for people trying to add their Pokémon to a freshly claimed Gym.

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Pokémon Go: How to fix ‘The Gym is under attack! Try again later’ error