Schannel errors are a problem initializing or validating the SSL certificate chain between your computer and the certificate authority (Sectigo in this case, formerly known as Comodo).
Most of the time this is caused by a temporary blip in the internet routing, networking software you have installed on your PC or some kind of software on your computer which is installing a certificate proxy so it can read your HTTPS traffic and it has an outdated certificate chain installed.
Certain Security Suite products are known to do this with their "web protection" engines (Kaspersky is a prime case), and ironically this makes your computer less secure - this is what is known as a man in the middle attack.
Killer Networking software also can cause this.
Proxy server restrictions can also do this, if you are using a Proxy Server (you might not specifically be using one, but your ISP could be)
Software development products also do this, but they do usually tell you up front, and normally they do not install their own certificate validation chain.
Some trojans/keyloggers are known to do similar things too.
What can you do?.
First a Reboot. Make sure it is not a transient error. Sometimes it is.
1.
Reboot your computer. Reboot your router.2.
Update your networking drivers/software, especially that will special "addons" like Killer.3.
Update Windows if it is needed.4. If you have a security product that includes a "web protection" engine, then I'd remove that section of the software. If you really want it, at the very least make sure it is up to date, as the lag in their updates to their certificate chains are usually what cause this error.
5. If you have software developer tools that do this too. Disable this.
6. Perhaps run from an admin command prompt:
A more advanced choice is (if you have a windows install disk/usb stick etc), from an admin command prompt (note this assumes you have a Windows 10 install in D:, if not adjust the path at the end):
- Code:
DISM /Online /Cleanup-Image /RestoreHealth /Source:D:\sources\install.wim
7. If its from your ISP using a proxy, ask them not to, or use an ISP that doesn't, or request they make sure their proxy does not proxy certificate validations.
8. Try using a VPN (this can bypass an ISP based proxy).
9. Other than that, it is usually a waiting game as it may be caused by the internet routing on your connection.
p.s. If you're really keen, and you want to rule it out for being something on your system, you could clean install Windows. This is not a recommended solution as I can't see how it would actually fix the issue if the above things did not, but if you have been meaning to do so anyway, it's an excuse, and something to do in the downtime.
Additional Note:
This error is probably occurring all the time for you, but browsers, which perform the same checks, have been known to hide it, whereas we take your security seriously, and do not make certificate signing checks optional, otherwise, what would be the point?!.
Posted: Thu Apr 02, 2020 7:44 pm