I currently have a message that says my 'anti-virus needs an update: click Check for Updates'.

I go into the Anti-virus/Anti-spyware section in the control panel, click 'Update Now' and an 'Update progress' window appears, which says it's trying to connect to the server.

However, this has failed every time, saying that it can't make a connection. Why is this happening and how do I update it?

I'm running the most recent version of Internet Security Suite.