Connection Refused

I have just loaded AsteriskNow and I am new to that and Linux. I am reading up on Linux but I seem to be having a problem with access to the AsteriskNow GUI from my PC. When I fist boot ANow I have not problem with access but after 1-3 days of uptime, seems to be inconsistent, I try to login and get the message, “Connection refused”. I have looked at the eht0 status and it seems to be OK. I also can not ping the ANow box once I start to get this message. Reboot fixes the problem.