When you turn off your box on some systems the system will drop recognition of the device and when you turn it back on it will give you the message about portal not recognized.
With some VPN services advanced tracking settings can prevent you from receiving the required packets to connect you to the portal you request.
I have a vpn that takes me a while to reconnect when I restart the box with the BUZZ TV enabled so it is easier for me to go to an app with less secure requirements and open the connection and then as soon as it comes up just go back to the BUZZ TV app and it will connect load everything an run like a top it could be a problem with your settings like my extreme settings on the vpn and the isp server you have.
There were some changes in some geographical areas recently that made his problem worse.
