Firewall no longer works

Bobfromhaverfordwest wrote:

On installing Big Sur, my Mcaffee firewall no longer works. What do I do? Remove Big Sur, try and get Mcaffee to fix it or throw the lot away and by a Microsoft computer. I currently favour the latter

Third party AV is not recommended— it typically does nothing but add issues to the macOS and competes directly with Apples own built in security:

macOS - Security - Apple https://www.apple.com/macos/security/

Apple Platform Security - Apple https://support.apple.com/guide/security/welcome/web

Uninstall all third party apps that are Cleaners/Optimizers/Anti-Virus

Uninstall McAfee security software from your Mac

1. 1. To make sure that the McAfee browser plug-in is removed correctly, close your browsers (Safari and Chrome) during removal.
   2. In the Dock, find and open the Applications folder.
   3. Double-click the McAfee Internet Security Uninstaller.
   4. Click Continue.
   5. Type your administrator password and click OK.
   6. Click Finish.

reference: How to install or uninstall McAfee software on macOS

Firstly, the macOS is Secure and does not require the third party software. macOS has a Builtin Firewall. Strongly suggest removing the third party software as per Developers Instructions.

If it were me, I would uninstall any and all McAfee software. Of course I would never have installed it in the first place.

And the error message says...?