It's very possible that you've encountered a maintenance session. Since you don't have control over it, the best way is to wait and try again. Additionally, make sure the application is allowed in the Firewall. Go to Start > Control Panel > System and Security > Windows Firewall > Allow a program through firewall (on the left). Reboot the computer and try to log in again. Additionally, re-install the application because all the remote data will be downloaded again after you log-in.