I have also been getting this alot lately on both my Sony and my better half's Samsung. If we use Virgin mobile, EE or public wifi with the same devices everything is fine. Virgin media broadband/WiFi is the common denominator. When I've got some time I need to ring then about it. If I have any joy I'll let you know.
I am also suffering this problem, as is my wife. Virgin media broadband / Wi-Fi is the common denominator. No problem with the same pages when using cellular data (Giffgaff). Another example site to add to the list is certain pages on the bbc sport website.
New user also, when I do have Internet which isn't all that often I reckon 50% of standard websites I get this response on phone and computer. BBC sport, accusivison weather, virgin media website. ... List goes on.