If you’re using STN’s trainer, this is why it isn’t working for you. STN’s trainer is for the Steam version of the game.
If you have the Uplay version of the game, you need this one: Watch Dogs 2 Cheats and Trainer for Uplay.
If you have the Uplay+ version of the game, you need this one: Watch Dogs 2 (Uplay+) Cheats and Trainer for Uplay.
Different store versions have differences in the game engine code which requires separate trainers to be made for them.