Is this virus warning legitimately from Apple

I am not a pro at fixing computers but I have gotten the same window while I was on the phone with an Apple advisor and he told me that it is a come on to get you to enlist them once you pay of course. They will probably run some sort of cleanup on your computer to get you to think that now it's working just fine something Apple can do if you call them during the day and just ask them to check for a virus. Take a screen shot to show them . They will go on your computer remotely. 1 800 myapple. Also you can just run first aid https://support.apple.com/guide/disk-utility/repair-a-disk-dskutl1040/macif you truly are experiencing any problems that's the first thing the Apple advisor will do. Also download and run (if you don't have it already) Malwarebytes https://www.malwarebytes.com/mwb-download/it's a free application that scans your computer for adware and virus'. Very good.

Unquestionably a scam. Clear out your browser's cache so that any malicious cookies are cleared out and to prevent this webpage from popping up again anytime soon. If you're using Safari, go to Safari preferences, then go to the Privacy pane. Click Manage Website Data, then click on Remove All. You'll be signed out of any websites that you have logged into, but any malicious cookies will be cleared from Safari.

No. It is a scam. Do not click on the content of any pop up.

Advise the site people (Activelearn etc) that their site has been infected.

Fake as a 6 dollar bill. No website can tell if you have a virus on your computer. Ever.

This is a scam. Ignore it. End of.