Here's why:
* Action Replay bypasses normal game mechanics: It allows you to modify game data, including Pokémon ownership and obedience.
* Legitimate Pokémon obey based on friendship: In the Pokémon games, you gain a Pokémon's trust and obedience by battling with them, leveling them up, and caring for them. This is not possible with a hacked Pokémon.
What you can do:
* Trade it to a different game: You can trade your Deoxys to a different game file or to a friend who uses a legitimate version of the game. This might reset its obedience status, allowing you to train it normally.
* Play with it as a "display" Pokémon: While your Deoxys might not obey in battles, you can still add it to your team and enjoy its appearance.
* Start fresh: Consider starting a new game file and obtaining Deoxys through legitimate means (like events or specific game versions).
Remember, using Action Replay or other hacking tools can compromise the integrity of your game and potentially affect your ability to play online with other players.