Firefox / Chrome do not open domain, Edge / cURL OK

Question

Latest Windows 10, fully updated Firefox 87 and Google Chrome 89. In the addressbar of FF/GC, enter https://www.facebook.com. There is zero network activity. GC reports ERR_CONNECTION_RESET, FF reports ns_binding_aborted and PR_CONNECT_RESET_ERROR. Edge opens the page immediately. With cURL (https://facebook.com) it reaches the site, does a 301 redirect to www. and the page is returned.

So this is not being blocked at the system level, only at the browser level where FF and GC seem to share the same block list somewhere. Other devices in this wi-fi network can access the site with no problem.

I've disabled firewall for public, private, domain. I've turned off and completely uninstalled Avast. I've disabled every Windows protection mechanism that I can find. I've stopped a number of services that look like they might be related to network activity. I've started others that were Manual/Disabled. Browser cache has been cleared. All addons and extensions have been disabled. The domain is not listed in any local block list that I know of, related to the browsers or otherwise, including in their latest security options related to trackers, ads, etc. The browser security is as disabled as I can make it and ads are not restricted. I've rebooted many times. There is no family protection setting. There is no proxy server, no VPN, no internal DNS.

https://157.240.11.35/ (One of their IPs) reports the connection is not private. That's interesting because it verifies that the browsers can reach the server. The message here is NET::ERR_CERT_COMMON_NAME_INVALID and I can see the DigiCert for *.facebook.com (not expired). So this seems to be related to the domain name and a factor of client-side DNS. "Proceed to 157.240.11.35 (unsafe)" does not work - the host redirects to www. which cannot be reached. I've used IPCONFIG /dnsflush. ("Does not work" means the connection failed, not 404.)

What is common to both browsers in this regard? To my knowledge I do not have any custom core network components. Maybe I did something to force a TLS version which Facebook doesn't support. (Just checked FF and set to 1 due to new higher default set in FF last year - no joy.) Following commonly suggested remedies, also set MTU to 1472.

Answer 1

The culprit here has been the Killer Control Center v2.0 application, installed on my Lenovo laptop by the manufacturer. This app automatically disables programs that are consuming resources when we are gaming. At some point I must have been on facebook.com when this app was looking for resource hogs.

Technically this is not at all related to Facebook itself (nor Avast) so I removed those tags from this Q&A.

It seems part of the reason this has been inconsistent, is that when I disabled a lot of active processes, this running application determined that facebook.com would no longer be a resource drain, so it disabled its block. But on restart all of the blocks were re-enabled.

I do not know why this only affected Firefox and Chrome, not Edge.
I don't know why this was working at all since the GameFast functionality is currently disabled.
I don't see a log anywhere that shows action was taken because of this block rule.
I don't understand why Facebook.com is in their list of "Applications", and not other sites. Facebook.com is accessed as a website and I have no Windows application related to that site.

A lot of people have complained that they can't access various sites from different browsers at different times. (Ref ERR_CONNECTION_RESET, PR_CONNECT_RESET_ERROR, NS_BINDING_ABORTED) There are many web pages, blogs, forums, etc that explain how to try to solve this problem. Let's add this to the list of known causes.
I will ask Support at Killer Networking to take a look at this. I do not fault their fine software. I'm just documenting my findings, and recommend this experience be used to improve Killer Control Center v3.0 (currently in Beta).