Incorrect SSL certificates

Flush the saved web data in Safari.

Please also post an EtreCheck report here. Download and enable full drive access and run EtreCheck. Then open a new reply here and then press the button that looks like a printed page to get a text input box big enough to paste the hardware and software configuration report here.

I deal a fair amount with SSL.

I do not trust most of the the security add-ons. Avast has had some shady-looking surprises. And the add-on security tools and add-on cleaners and add-on VPN clients can and variously do intercept comms, and which can clobber SSL traffic. Well-written SSL apps should detect and block the interception, but not all do.

The EtreCheck report will show what’s loaded here.

Do you have any proxy settings?

Click on advanced on the active internet connection in Apple menu -> System Preferences -> Network after selecting the green port. If there are proxies present, remove them and try again after reboot.

Hi Frank, glad to see you rid yourself of Avast.

Go on the Apple certificate page:

https://www.apple.com/certificateauthority/

Download the Apple Intermediate Certificates

Apple IST CA 2 - G1 Certificate (direct download)

Double click the downloaded certificate to install it in Keychain Access.

You should see it now, in login certificates.

Try this browser...

https://brave.com/

On no evidence, I'd guess that some of the anti-malware has cached the certificate, or maybe something odd with the Dashlane password manager.

This Mac has various apps that would lead me to wipe and re-install, as I've found that to usually be the most expeditious approach for recovery. You probably won't want to do that—I used to not want to preemptively reinstall, too—so here you'll want to remove Avast, ESET, and Trusteer/Rapport. Or as I usually do now, back up, back up again, wipe, reinstall macOS, and restore current versions of the apps needed, and generally avoid add-on security apps, add-on VPN clients, add-on anti-malware, add-on cleaner apps, and related.

It's unclear if that WD Discovery Service is part of some WD app-update stuff, or if it's junk. But it's broken, whatever it is.

Flash and Silverlight would be gone here, but those are unlikely involved.

I'll assume you know about the Chrome remote desktop.

Add-on anti-malware apps have had a very long history of being wrong, of introducing instabilities, of crashes, of hangs, and all sorts of weird issues. For seemingly negligible benefits for you, over the Apple anti-malware. Avast was re-selling users' complete browsing and purchasing histories, so they probably made some money here. The add-on cleaner apps can cause similar issues with macOS environments, and have variously caused corruptions. Even when working properly, these add-on security tools are indistinguishable from malware that just doesn't like to share, given how these tools tie into macOS.

Are you using any VPN or Anti-virus software?

I am telling your problems are that your computer is infected with some severe malware. Your issues need to be remediated by a virus cleanup. Some of it is manual, some can be done with your built-in software. You have self defeated yourself by installing BOTH Trustear and Avast. Having two virus utilities effectively cancel each other out.

1. Remove Trustear with their built-in uninstaller. If it doesn't have one, get AppDelete to do it for you.
2. Run Avast full scan and Quarrantine whatever it finds.
3. Download and run Easy Find after following step 4.
4. Boot the machine in safe mode with the shift key.
5. Open Easy Find and search for files by MacPaw and Zeobit and Chromium.
6. Remove all files found in step 5.
7. Delete Cleanmymac from your application folder and MacKeeper. Neither belongs.

Chromium is typically only on as Malware. Trusteer interferes with the ability of Avast to run properly.

CleanmyMac and any MacPaw and Zeobit files should be removed in safe mode (hold the shift key) with Devon Technologies EasyFind. These are malware not able to be removed by other means