Site not found can be down to a number of things out side of the control of this board.
It could be down to your coumputer.
It could be down to your software.
It could be down to your connection to the isp.
It could be down to your isp's connection tio the net.
It could be down to any one of the hops that that connection makes to get to its final destination.
it could be down to the server.
There are loads of others besides these.
Why do people automatically assume that just becasue they get something like a 404 that it is the site they are connecting to at fault?