Reset admin password

I've installed and configured the Secure Connect Gateway.

At the initial configuration I had to setup a password for the admin account for the webinterface. I generated one and it was accepted. After that I completed the configueration and adding devices.

But now, when I try to login, I get an error "We can't continue with this password. Make sure your password doesn't have any invalid characters, then try again."

I don't know what characters are invalid, but it has some special characters in it. Although, these were not identified as invalid when setting up the password.

Can someone tell me how to reset the admin password? I'm able to login with root on the console, but not in the webinterface anymore. That only worked on the initial setup page.