When I try to access a site, it says "Connection has timed out The server at jdlhighschool.eduvisiontest.info is taking too long to respond.
The site could be temporarily unavailable or too busy. Try again in a few moments.
If you are unable to load any pages, check your computer's network connection.
If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web."
What are the possible reasons for this problem?
Most of the time (if the rest of the Internet works for you), it is the first one.
The site could be temporarily unavailable or too busy. Try again in a few moments.
This means that problem is at the server, nothing you can do (except maybe send them an email).
Depending on the site's traffic patterns and administrator attention, a few moments could be days, though...
There's also a 4th possible explanation: Wherever you are has a proxy or firewall that is blocking access to the site, and doing so in a way that doesn't simply say "no" but instead doesn't give you any answer.
For what it's worth, I tried accessing http://jdlhighschool.eduvisiontest.info/default.aspx with my browser and got a page right away.