@dongxu - First of all, please do not make multiple posts saying the exact same thing. This is spam, which is not welcome here (so I removed it). Ask once and be patient.
- Make sure WeMod is whitelisted in your antivirus. Instructions: "Wemod failed loading the cheats into your game" / "We’re having trouble downloading the cheats" - #2 by Ravenfyre.
- Make sure you have the game from Steam, as this is the Steam trainer.
- Make sure your game is legitimately purchased (as in not cracked/pirated).
- Make sure your game is up to date.
- Make sure you are using the newest trainer release by pressing the History button under the Play button.
- Make sure you are not attempting to use the trainer in multiplayer games.
- Launch the game first. Wait on the main menu for 5 minutes. Alt+tab to WeMod to press Play.