Apparently updating firefox to version 65 causes connection not secure everywhere. If I disable shield control there is no problem. I don´t know if is a problem with Firefox or Avast.
Thanks.
Same issue here. I’m pretty certain disabling https scanning would end it but I’m not going there.
I think that we are going to be seeing more of this.
No problem here with Firefox 65 (x64) and Avast Free 19.1.2360 running on Windows 10 (x64).
I think that we are going to be seeing more of this.Just an observation (but may be pertinent). The last time this flurry of reports happened was when Avast went to version 14: the problem was that the Avast certificate changed and a re-import of the certificate was the solution.
At that time the Avast cert was set to expire in 2024. I just checked, and the current cert is set to expire in 2040, so it looks like it has changed again.
NOTE: in either case below, you must export the certificate from the latest Avast you are using.
So, as a first step, see if this helps https://support.avast.com/en-eu/article/Troubleshoot-invalid-email-certificate.
If not this may help (the reply was for Thunderbird, but applies equally for Firefox): https://forum.avast.com/index.php?topic=224844.msg1492272#msg1492272.
I did this :
That would have been my next suggestion if https://forum.avast.com/index.php?topic=224844.msg1492272#msg1492272 doesn’t work 
I personally am not seeing this issue with latest FF
Same, although when I go to see site security, it now says it’s verified by Avast. And it’s like this in every site, it certainly was not like this before
Confirmed no issue. Not aware that Avast ever stopped verification, but avast forum shows DigiCert, Inc as secure certificate
It was probably an individual issue then, what got fixed yesterday when i reinstalled Firefox and clean installed Avast.
I did what abruptum did: https://www.youtube.com/watch?v=lFMu0UVgM24 and fixed the problem, but I´m concerned on security issues.
Is doing that all right?.
Thanks.
I’m curious about that as well.
I am not an expert, but I think by enabling that preference in about:config, you are “telling” Firefox to use system certificates like other browsers like IE,Chrome etc.
If you write down and save your setting changes as you make them, you should be able to revert.
Having said that, I looked and found security.roots here was set to false. Do not need to change. No certificate errors.
I have just updated to FF65 on my win10 system with avast free 19.1.2360 and whilst I don’t any error as outlined in Reply #2
But the detailed information shows the use of TLS 1.2, I thought things were moving on to TLS 1.3.
Funny thing was, that it did not start immediately after the update, but after a while.
I tried a lot of pages and they all fail, like amazon.de, ebay.de, google.de (I am German as you see ;-))
My wife did some banking in the morning. I came to the running computer and used an open Firefox session.
I WAS on amazon.de. But then, following a link to a product, I got this “This page is not secure” or whatsoever message. From then on all pages failed without exception.
Had to switch off the Web Shield (?), “Web-Schutz” in German to get here…
Ugh, this just happened to me.
Everything was working fine and then I restarted Firefox to update it and boom, not secured everywhere.
I toggled the root option in about:config and it did work properly after that, but it seems like from reading up on it this is another issue with Avast and Firefox talking to each other given the webshield thing is also a way to get it working? But it’s also somehow only happening to certain unlucky people???
All I want to know is that Avast are aware of this and in contact with Firefox, to the point of something happening about it hah 
Until then what is the best and safest course of action to deal with this thing, toggling the setting? Turning off web shield seems worse? Any help appreciated 
Fully hoping to wake up to a solution, it’s late here.
Today’s update to Firefox 65 blocking all websites on one machine. Yesterday’s update on this machine, so far, so good.
I looked at some of the fixes and think I will wait until Avast and Mozilla figure this out. Pays to wait to upgrade.