Firefox 4 worked perfectly for me, but Firefox 5 says a connection could not be established.
Today I upgraded from Firefox 4.0.1 to Firefox 5.0.1. That's when all of a sudden I was unable to go to any sites.
"Unable to connect
Firefox can't establish a connection to the server at [insert site here]
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."
Today I upgraded from Firefox 4.0.1 to Firefox 5.0.1. That's when all of a sudden I was unable to go to any sites.
"Unable to connect
Firefox can't establish a connection to the server at [insert site here]
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."
Opaite Mbohovái (2)
It is best for you to read this article Firefox can't load websites but other browsers can
Maybe your firewall is blocking it. Some firewalls will block an application that is updated.