iMAC and MAC BOOK AIR Can't connect to UK govt website!!

I tried that site and it loaded fine for me. I tried it on several Macs running OS from 10.11 to 10.15, it loaded on all of them. If you have anti-virus installed, even when you turn it off it is still there and may impact your computer's behaviors. Other background programs you may have installed can also impact sites not loading. By the way, it also loaded on the work laptop I have on which my employer requires Symantec AntiVirus Enterprise to be installed (I can't even remove it from that laptop if I wanted to).

I don't doubt you when you say they won't load. What do your two computers have in common (I imagine you have set them up similarly and installed similar software) that is different from a plain computer just purchased?

DrewTried wrote:

I am curious why the app is in your opinion unnecessary?

Thanks once more

Andy

Because there are no Mac virus' out there to infect your computer.

Because third party antivirus apps use system resources while providing no benefit.

Because third party antivirus apps cause problems as you have discovered.

macOS - Security - Apple

Set up your Mac to be secure - Apple Support

Protect your Mac from malware - Apple Support

Effective defenses against malware and ot… - Apple Community

Why would you reinstall an unnecessary third party antivirus app, especially when it already demonstrated that it causes issues?

There is malware that you can load into your Mac but a third party antivirus app will not protect you from such malware. Read my fourth link above.