The Cisco AnyConnect add-on doesn't send the proper information like the password or the group number to the vpncli.exe DOS window to establish the VPN connection.
As example, only the half of the password is sent to the Cisco AnyConnect window.
The Cisco AnyConnect add-on use sendkeys to send information to the vpncli.exe window. The issue that we encounter is caused by the Windows UAC feature. Enabling/Disabling UAC on your computer should resolved the issue.
On your computer, go in Control Panel - User Account - User Account Control Settings:
•Select Never Notify to turn off the option.
•Select Notify me or Always notify to turn on the option.