Can you provide more details on the issue you are facing? Are you using your PDN credentials to try and log in? Are you seeing the log in screen and then getting an error when you try to log in? Are you getting an error immediately upon accessing the link?
I had no trouble logging into the system using an administrative account.
One thing to try would be to access the link in a private browser session (i.e. a Chrome icognito window, IE InPrivate browsing session, or Firefox private window). This would help us understand if it is a session issue.