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}

As I said I already followed all of these recommendations. I even tried it a second time. I also followed the recommendations in the other article that has you disable IPv6, etc. Nothing works.

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

Under Advanced, Select Network.

[v56+] 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.

I have tried switching back and forth between the two already with no success.

It's just such a strange issue. How does it suddenly stop working?

I have Opera and Chrome also on the laptop and they both work fine. Firefox is my go-to.

I called for more help. Do a total shut down of the computer. Then unplug the power from all routers and modems for a slow count of 10. After, start everything up again.

It is fixed. My laptop did some Windows updates and when it rebooted it did a chkdsk which found a couple of issues. When it rebooted Firefox was working again.

Thanks for your help folks. Sometimes weird things happen that cause problems. Fortunately in this case it eventully got detected and automatically fixed.

That's good to hear. Please flag your last post as Solved Problem so others will know.