UltraVNC authorization failed

VNC Server won’t let you connect without supplying a password, unless the server is explicitly configured to use no authentication. Note that you can also set a separate «view-only» password.

Configuring the WinVNC server password

1. Right click on the VNC tray icon (if there is no icon, run Start Menu → Programs → UltraVNC → UltraVNC Server).
2. In the password field, enter your password. While typing you see the classical **** characters used to hide what you are typing.
3. Click OK.

The undocumented catch

Eight characters is the minimum required, even if it is not documented. If you set fewer than 8 characters the server will not complain, but from the client you will never be able to connect and you will get «Authorization failed».

Choose a password mixing special characters, digits and letters, so that it is hard to guess and reduces the risk of a dictionary or brute force attack.