Does the site work or not?

Question

Domain Name System

The bottom line is this:
There is a site that works for 15 minutes and ceases to be available - while there is nothing in the logs about this.
What could be the problem?
I've been struggling with this problem for the 2nd day and I don't know where to dig.
Thanks in advance

Answer 1

Does it respond to pings? Telnet port 80 available?

Answer 2

come on site ;)