If you already have the client, open the "World of Warcraft/Data/enUS/realmlist.wtf" file.
Delete everything and enter this: set realmlist logon.virtuswow.com and save the file.
Start the game using WoW.exe (do not use the Launcher) - login and play!
Unable to connect?
Make sure you are logging in with your account name and not your email address.
Recheck that your "realmlist.wtf" file is really set to: set realmlist logon.virtuswow.com
If it does not accept to be modified, right click on the file and unselect the "Read-only" attribute.
Dont forget you must login using your username and password, not your email.
Make sure you are on the correct version of WoW (3.3.5) before you try to connect to the server.
Please check that the server is operational on the front page.
If you still have trouble after this, get in contact with us on Discord.