"The update server can not get the patch code files."
Translated with translator from korean:
1. Move to the folder where the closure is installed.
(Default installation path is C: \ Nexon \ Closers)
2. CLOSERS & CW files
Right click - Properties - Compatibility - Check this program to run as administrator.
3. Login to the homepage and run the game. End.
Not sure if it works. And I dont know do you run your game as admin already, but if you do then idk, yet.
Welp, then you cant play, hahaha