I have a Yarvik tablet 4.1. We set it up and it was working fine,until today. All I can get is the BT Open Zone.com 'site, when I tried to access my server, it just said problem with authentatation, so I can't access my emails or get on the web. I first had this problem when we first bought the tablet, was just getting this advertisement for BT. But I thought we had cured it. Any help please. Thank you.