I'm not sure if this is the correct place to be posting this or not.

I have recently installed squid and squidguard as a web filtering system on my network. I have followed the official ubuntu guide and it works perfectly when I reboot my server. The web filtering works for the first about 2 minutes by allowing me onto any websites other than the sites which I have blocked which are currently the same as the ubuntu guide states. Has anyone else had this issue or able to help me in fixing this problem.

Any help will be greatly appreciated.
Many Thanks

Ubuntu Squid Guard Link