Hello,

The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information.
Note: This will cause you to lose any Extensions and some Preferences.

• Open websites will not be saved in Firefox versions lower than 25.

To Reset Firefox do the following:

For Firefox versions previous to 29.0:

1. Go to Firefox > Help > Troubleshooting Information.
2. Click the "Reset Firefox" button.
3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
4. Firefox will open with all factory defaults applied.

For Firefox 29.0 and above:

1. Click the menu button , click help and select Troubleshooting Information.

Now, a new tab containing your troubleshooting information should open.

1. At the top right corner of the page, you should see a button that says "Reset Firefox". Click on it.
2. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
3. Firefox will open with all factory defaults applied.

Further information can be found in the Refresh Firefox - reset add-ons and settings article.

Did this fix your problems? Please report back to us!

Thank you.

Hello, thanks for answering my question, but all this began exactly because of that button. I'm using firefox for several years, never had a problem, then some messages began to appear at the bottom of the page about firefox getting slower and how I could fix that pressing that button, that's what I did, and then firefox stopped working and I couldn't access to several sites, because a security warning appears saying that that connection is not secure. Then I removed mozila firefox and installed it again for last version, but it is happening again with the same sites'. I read your recommendation and tried the reset button once again but it continues with the same problem. If I select health bottom from menu help appears the following message: "This connection is not reliable Asked Firefox to connect securely to fhr.cdn.mozilla.net, but we can not confirm that your connection is secure. Normally, when you try to connect securely, sites have the security ID to prove that you're on track. However, the identity of the site can not be verified. What should I do? If you usually connect to this site regularly without problems, this error could mean that someone is trying to impersonate this site and as such should not continue. "

"Esta ligação não é de confiança

Pediu ao Firefox para se ligar com segurança a fhr.cdn.mozilla.net, mas não podemos confirmar que a sua ligação é segura.

Normalmente, quando se tenta ligar com segurança, os sítios apresentam a identificação de segurança para provar que você está no bom caminho. No entanto, a identidade deste sítio não pode ser verificada. O que devo fazer?

Se se costuma ligar a este sítio regularmente sem problemas, este erro pode significar que alguém está a tentar fazer-se passar por este sítio e como tal não deve continuar."