There are 2 possible solutions:
- You are launching the game through its .exe instead of Steam - launch through only the Steam client.
- You need to run Steam as administrator. Shut down Steam, right click the Steam icon on the desktop and select 'Run as Administrator'.
Players have been reporting this issue persists after the above fixes and other forms of troubleshooting. If you cannot resolve this issue with the above solutions, please contact Nexon Customer Support at the URL at the top of this post to get further assistance and provide additional info to the CSN:Z Team towards resolving this.