What's your computer system and Firefox version?

Some problems occur when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again;

• Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
• Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see

Configure firewalls so that Firefox can access the Internet. {web link}

Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

Which error message(s) do you get?

FredMcD, I did what you said (I had already done this), and Firefox still will not connect with any websites. I tried starting Firefox in Safe Mode, and the problem was still there.

jscher2000, This is an example of the error messages I get, with all websites: "Unable to connect Firefox can’t establish a connection to the server at mg.mail.yahoo.com.

   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."

The problem is not with the websites I am trying to connect to -- I know this because I can connect to those websites with other browsers (Edge and Chrome).

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select Network.

[56+] Type about:preferences#general<enter> in the address bar. Look for Network. +++++++++++++++++++++ Look for Configure How Firefox Connects and press the Settings button. If you are using a proxy, make sure those settings are correct. If there is no proxy, first try No Proxy. If there is a problem, then try System Proxy.

FredMcD,

I have no idea whether I'm using a proxy or not, or even what a proxy is.

At this point, I need to give up and get on with my life. I will just not use Firefox anymore. I can always use Edge or Chrome, although Firefox had features I liked a lot.

Are you listening, Mozilla corporate people? You have just lost a customer. Is it really so impossible to assign one of your employees to the job of helping customers with problems? Do you HAVE to leave it to well-meaning amateurs to try to help each other??

Please don't misunderstand, FredMcD and jscher2000 -- I am grateful for your attempts to help me. But, why can't Mozilla itself do that? Why do they leave it to customers to help each other, and not assign some of their professional, paid tech experts to help? Other tech companies do the same stupid thing. Are customers not important to them?

Support Volunteers can't make changes to Firefox and do not need that. Also can not do the job unless there is a willing person to do so and to take direction and to not say it is not their Security Software and brush that aside.

To submit suggestions for new or changed features, may I suggest: Feedback: https://qsurvey.mozilla.com/s3/FirefoxInput/