User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1) Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:18.104.22.168) Gecko/20071127 Firefox/22.214.171.124 When working at home last night I couldn't browse on my laptop using Firefox (IE7 and Safari worked fine), although my wife, connecting through the same wireless network was using Firefox without problems. I tried online chat with zzxc (http://support.mozilla.com/tiki-view_forum_thread.php?forumId=1&comments_parentId=204451#threadId204500) who wasn't able to help resolve the matter. This morning, using the same laptop hard-wired into my company network, Firefox worked fine. However, it wouldn't work if I disconnected and tried our Office Wireless Network. Solution was to change the Firefox proxy connection settings. I have searched the knowledge base this morning and not found a similar report. Therefore I have logged on to make the suggestion that this simple solution should be in the KB or FAQ's Reproducible: Always Steps to Reproduce: 1. 2. 3.
This is documented in this knowledge base article: http://support.mozilla.com/en-US/kb/Firefox+cannot+load+web+sites+but+other+programs+can#Connection_settings In this case, it seems you had configured it to use an internal proxy server only available on your work connection. If a connection is refused or the address is invalid, this will result in a "Proxy server connection" error. If the connection times out, however, the error message does not specify a proxy server. There is already a bug to change this message to be correct - bug 197697. Since there is already a knowledge base article that covers this, I am marking this bug "works for me." I will change that knowledge base article to mention the "connection timed out" error specifically as a problem that can be caused by proxy servers, to make it easier for people to find this solution.
v Error message added. <http://support.mozilla.com/tiki-pagehistory.php?page=Firefox+cannot+load+web+sites+but+other+programs+can&compare=1&oldver=14&newver=15&diff_style=sidediff>