problems using Firefox?

Hello. I just installed firefox, but could not visit all sites. that says "Firefox is configured to Use a proxy server that can not be found. "What can I do? Thanks.

Try going to Tools> Options> Click the General> tab "Connection Settings" and try one: direct Internet connection or if that fails, then automatically detect proxy settings for this network. The "direct connection to the Internet" should work as well and mine is set up. The auto detect configuration settings proxy would work better if you were on a network. I hope that helps, otherwise I will update this reply to you with other ideas! Good luck! Whatever that making use of Internet Explorer! lol.

How to set up proxy in Mozilla Firefox