The web server does not work. What might be the problem? Now is your time to ask questions to reach an answer. No: the system is not dead (e.g. power failure), it hasn't crashed (e.g. kernel panic), there is no network failure (it responds to pings/ICMP requests, but does not respond to HTTP requests), there is plenty of memory and processing power available (i.e. no RAM or CPU saturation), the web service is running (i.e. no crashed processes), there are adequate child threads available to clients, etc.
