Hi I have an unusual situation where the URL keyword filter is only working interminttently for certain users on the LAN.

For example I have iplayer dailymotion twitter.com as three keywords in a keyword object and a group that containts this object
The URL content filter contains this group to Block.

Going to for example http://www.twitter.com/ gives me
The website declined to show this webpage
HTTP 403
rather than the normal block message

and going to https://twitter.com/ is working which it shouldn't be.

My router is a 2830 on fw 3.6.4 db 232201

It also seems that certain browsers are getting further than others. This is very strange as they should all give the bespoke message I have setup in the router regardless of secure or non secure web access.

Any ideas?
thanks
Rob