APM site slowness/timeout

I do not believe so because when I go to resolve the address from the web right after saving the policy for access, the site resolves for logon and I can reach to the full webtop successfully. Fast forward about 3 -4 hours of no use and the site times out when attempting to reach it. Our firewall shows that the attempts are coming back as incomplete. Funny part is, usually, if I keep trying the site will eventually "wake up" and start resolving again. This happens internally and externally. I was just wondering if anyone had enough experiencing with these to know what to look at? My co worker believes it is a monitor that is failing, however, that does not appear to be the case.