Hi Michael9999, this error normally would only occur if:

• You (or an add-on) manually changed some Firefox security settings
• Your browsing is routed through some older security software or proxy that is not current with security standards
• Your browsing is intercepted by malware

To check your Firefox settings:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful or accepting the risk.

(2) In the search box above the list, type or paste TLS and pause while the list is filtered

Do any preferences show as "user modified"? You can right-click > Copy and paste those into a reply for an opinion on whether those could be an issue. Or reset modified preferences using right-click > Reset.

(3) In the search box above the list, type or paste SSL and pause while the list is filtered

Do any preferences show as "user modified"? You can right-click > Copy and paste those into a reply for an opinion on whether those could be an issue. Or reset modified preferences using right-click > Reset.

These are okay to disable:

• security.ssl3.dhe_rsa_aes_128_sha
• security.ssl3.dhe_rsa_aes_256_sha

Thanks I tried those about:config codes but all looked ok and set to default. I tried to go to gmail login in via a sesrch but that didn't work and I get the same message from google search!

Thanks I tried those about:config codes but all looked ok and set to default. I tried to go to gmail login in via a sesrch but that didn't work and I get the same message from google search!

Could you test:

(1) in a private window (Ctrl+Shift+p) -- to rule out any cache/cookies issue from regular windows

(2) in Firefox's Safe Mode? In Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

You can check your browser.

• https://www.ssllabs.com/ssltest/viewMyClient.html

I have this problem with the latest Firefox with any search engine, including Google. It comes and goes but occurs with increasing frequency.

I have done everything on this page: using Firefox in safe mode or private makes no difference. The browser check shows no problem. I have also re-installed Firefox and rebooted my computer endlessly. If I know a website, I can load it with Firefox without difficulty, for instance, from a bookmark. It is searching the internet which is impossible.

Strangely (and indeed the only reason why I can pick up this site) SeaMonkey's browser works absolutely fine - and has the same browser check result as Firefox Quantum.

This is on a Lenovo Yoga, about a year old, with native Windows 10 up to date.

Hi YellowOars, could you experiment with your proxy setting:

• Windows: "3-bar" menu button (or Tools menu) > Options
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the search box at the top of the page, type proxy and Firefox should filter to the "Settings" button, which you can click.

The default of "Use system proxy settings" piggybacks on your Windows/IE "LAN" setting. "Auto-detect" can lead to a flaky connection. You may want to try "No proxy".

Any difference?

jscher2000 thanks so much for coming back so quickly. As I said in my post, this is a fault which comes and goes (intermittent faults are always the most difficult to track down). I've been away from the computer for five hours and the fault has disappeared in the meantime.

Anyway, I've done as you suggested and "No proxy" seems to work. I'll leave it like that and post again in a little while to say whether the fault has returned or not.

In my last post, I remarked that SeaMonkey worked fine, even when Firefox did not. I have since found that when Firefox can't search, nor can Microsoft Edge (which I never really use). Microsoft Edge gives the same error message as Firefox. I don't know whether that helps or muddies the water further.

Hi YellowOars

You can also do a malware check with several malware scanning programs on the Windows computer.

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware

Please scan with all programs because each program detects different malware. All these programs have free versions.

Make sure you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  http://www.malwarebytes.org/mbam.php
• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  https://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender:
  https://windows.microsoft.com/en-us/windows/using-defender
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  https://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• Anti-rootkit utility TDSSKiller:
  https://support.kaspersky.com/viruses/disinfection/5350

https://support.kaspersky.com/viruses/utility

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked