Norton VPN blocking certain internet pages such as BBC news

Hi
I have recently added Norton WiFi security VPN to all my iOS and Windows 10 computers. 
Initially everything worked fine and I had confidence that I was opening and utilising the VPN correctly.

In the last two weeks, BBC News website has intermittently been blocked (along with other websites) with the following error message:

An error occurred. Sorry, the page you are looking for is currently unavailable. Please try again later. If you are the system administrator of this resource then you should check the error log for details. Faithfully yours, nginx.

This happens on all my devices and has become very regular more recently.

Please advise as to what is happening?

Many thanks

Michael