This just started today after years of no problems. Why? 

IP blocking is usually caused by multiple failed logins (with incorrect passwords), or other detected unusual activities. It is designed for better security. When it happens, please check if any person, computer/device or software tried to log in with an incorrect password(s). Web browsers, client software and mobile devices may save an old password. If you changed your password, please make sure to update your password in all programs/devices. Your IP address will be automatically unblocked after 2 hours of no activities. If it is urgent, please contact DriveHQ customer support and provide your (public/external) IP address.