FireFox cannot access nearly any webpage - SSL error

[jlj945]

Hi all, I’m having a rather annoying problem with one of my machines. I use FF as my main browser on about every machine I have, with various operating systems. Most are Macs or Linux.
This problem is occurring on a PC, running Windows 10 and FF 83. While going to almost any site I’m greeted with “ SSL_ERROR_RX_RECORD_TOO_LONG”. Including google, and mozilla’s own support site. However it does load the page that clicking on “learn more” brings you to. I am also able to access my routers configuration page.
It doesn’t happen in any other browser on the computer, and FF works fine on all my other machines. Seems to be an isolated issue.

I’ve refreshed FF, changed SSL to accept down to v1, and still can’t load anything. I’m not really sure what to do at this point, I’ve never seen this happen before on a single default-configuration browser.

[Sabin]

I would be inclined to doubt that's your issue, but I'll mention it just in case (hey, who knows, right?), I once had a similar problem many years ago, also affecting only Firefox, on a Windows 7 machine.
The culprit turned out to be Avast, that insisted on installing its own root certificate to check SSL traffic, but didn't do it properly, although the specifics as to why it only affected Firefox remained alien to my understanding, apparently FF treats certificates differently, but no idea how. Deinstalling Avast and rebooting the PC fixed the issue.

[jlj945]

I would be inclined to doubt that's your issue, but I'll mention it just in case (hey, who knows, right?), I once had a similar problem many years ago, also affecting only Firefox, on a Windows 7 machine.
The culprit turned out to be Avast, that insisted on installing its own root certificate to check SSL traffic, but didn't do it properly, although the specifics as to why it only affected Firefox remained alien to my understanding, apparently FF treats certificates differently, but no idea how. Deinstalling Avast and rebooting the PC fixed the issue.

I don’t have Avast, only the default Windows 10 Defender. I suppose it couldn’t hurt to see if is causing it though.

[Cheekeh Munkeh]

I'm also getting the occasional random SSL error since updating to v83, except they're "SSL_ERROR_BAD_MAC_READ"

Nothing else in my configuration has changed, and not running any proxies nor IPv6. HTTPS-Only Mode is not enabled. No AV or other network-affecting software is running.

Perhaps something has changed in the way v83 is handling secure connections.

[tonydi]

I've been seeing the same error as Cheeken Munheh. In fact I could just copy/paste his post because I have the exact same configuration. As he said, it doesn't happen all the time, perhaps a few times a day. Still, this is all brand new since moving the v83 64 bit on the day it was released.

[malliz]

Hi all, I’m having a rather annoying problem with one of my machines. I use FF as my main browser on about every machine I have, with various operating systems. Most are Macs or Linux.
This problem is occurring on a PC, running Windows 10 and FF 83. While going to almost any site I’m greeted with “ SSL_ERROR_RX_RECORD_TOO_LONG”. Including google, and mozilla’s own support site. However it does load the page that clicking on “learn more” brings you to. I am also able to access my routers configuration page.
It doesn’t happen in any other browser on the computer, and FF works fine on all my other machines. Seems to be an isolated issue.

I’ve refreshed FF, changed SSL to accept down to v1, and still can’t load anything. I’m not really sure what to do at this point, I’ve never seen this happen before on a single default-configuration browser.

Do you use any extensions/addons?

[dickvl]

Are you possibly using a VPN or proxy ?

You can check the connection settings.
Options/Preferences -> General -> Network -> Connection -> Settings

See also "Firefox connection settings":
https://support.mozilla.org/en-US/kb/fi ... owsers-can