@Talush6370 you probably got this msg while the server was down ! or .. even myself i have to launch the game 2 times before it open or i get this pop up
Same here. I haven't been able to log in for maybe 2 months now with this same issue. I've followed every possible step that people have mentionned but still can't log in. Normally clicking on different compatiblility modes + right click run as admin would work after 2-3 times, but now it never works. Please help us.
First make sure your files are up to date, if you are unsure download the entire setup and delete and uninstall the old one. Try different compatibility modes. Spam the client until it opens, it has worked for many people who had similar problems.