I received this message after removing malware "buzz-it ads"
The proxy server is refusing connections
Internet connection is working. It's just not connecting with firefox and I cant uninstall it because it's my only "working" browser.
Could you check your Firefox connection setting?
Windows: orange Firefox button (or Tools menu) > Options > Advanced
Mac: Firefox menu > Preferences > Advanced
On the Network mini-tab, click the "Settings" button. The default setting is "Use system proxy setting" but you also can try "No proxy."
I'm not sure how thoroughly you swept for the presence of other possible malware. This article suggests some tools for that: Troubleshoot Firefox issues caused by malware.