Access denied (policy_denied) for yahoo mail using android network three

Strange one this, when trying to access my email on Yahoo mail i get:

Access Denied (policy_denied)

Your system policy has denied access to the requested URL.

For assistance, contact your network support team
Ok tethered my mobile to my pc to look for a solution.

was unable to log in to yahoo mail through any of my browsers. Was however able to log into my recent login activity which showed me


11:45 PM Browser Logged In United Kingdom

11:44 PM Browser Logged in to Mail United Kingdom

11:41 PM Browser Logged In United Kingdom
11:37 PM Yahoo! Mobile Logged In Iceland

11:20 PM Browser Mail Access United Kingdom

11:18 PM Browser Mail Access United Kingdom

11:09 PM Browser Mail Access United Kingdom

10:49 PM Browser Logged in to Mail United Kingdom

10:40 PM Browser Logged in to Mail United Kingdom

from tonight which seems strange ??

also thankfully have operamini on my android and i am able to access my mail through there which was about 11:40.

Is this a network problem with my provider threemobile or has my browser been hijacked???

Any help would be appreciated, thanks