404: a host server responded to your browser, but it cannot find the
requested URL, which usually means the document was moved or even
deleted. Or it could mean that you clicked a bad link; you may be able
to fix this by simply starting over and typing the URL into the
address field.
403: the requested resource is forbidden, which generally means you
don't have the privileges needed to access that page. Recheck the URL
and try again, or look around elsewhere on the site for another way to
get to the page you need.
503: the server is probably too busy to handle an additional
request for service, or it could be some other problem along the
Internet. Try back in a few minutes.
common browser error messages Unable to locate server: your browser
wasn't able to verify that the domain name exists. The server name in
the URL you sent is probably incorrect.
Host unavailable: the actual wording of this message depends on the
browser you're using. Anything similar to this means that the domain
name you're attempting to access does exist, but it's currently not
responding to your request. This usually occurs when a server is so
busy that it is effectively offline, when it is down for maintenance,
or when it is temporarily unavailable because of some other problem.
Wait and try again later.
