You have to use a valid & activated
UnrealSoftware.de account to login in-game!
Too many failed logins - wait for at least 15 minutes
CS2D will automatically decline any login attempt after several failed logins. This is a protection against brute-force attacks. Please wait at least 15 minutes and try again afterwards! Do NOT try to login during those 15 minutes!
Firewalls - configure/disable them!

CS2D needs full internet access for the login to work!

Configure/disable all software firewalls (if you have any)

Configure/disable all hardware firewalls (if you are using a router or comparable hardware)

Configure/disable the Windows firewall (if you are using Windows)
Password file somehow damaged - remove it

Quit CS2D

Go to the folder where you installed/extracted CS2D

Open the sub-folder "sys"

Delete the file "usgn_pw.dat" in that folder

Start CS2D

Enter your correct password again in the settings and see if it works!
Other important points - check account and U.S.G.N. state

Make sure that you are using your UnrealSoftware.de user name and password

Make sure that your account is activated and working (
login at UnrealSoftware.de)

Open the console for detailed error information

Maybe the U.S.G.N. is down. Check the state at
USGN.de (try again later if it's down)
Other possible solutions - restart stuff

Restart CS2D

Restart your PC

Disconnect from the internet and reconnect

Restart your router

Pause all uploads/downloads and quit programs which are using the internet

Re-install CS2D to another location (do NOT install to C:\program files!)
Nothing helps? Try to change your password!
Login at UnrealSoftware.de

Open the profile (link is at the top right corner of the page)

Click "Change Password" and change your password

Change the password in CS2D as well and close CS2D afterwards

Wait at least 5 minutes

Start CS2D and try to log in with your new password!
Forgot your password/account data? No Problem!
Just visit
www.UnrealSoftware.de/recover!