Go to cf folder , and search for "Version.ini" , open it ad increase the number in latest client +1 , as example of it was 1001 make it 1002.
Or just re-install the game.
i reinstall the game and i have the same problem help please
Try downloading latest client , scan your PC for viruses.
Install it again (Antivirus / Firewall ) must be turned off during installation.