Doing this for 2 years now, unplug and plug the cable back in. Windows 11 is a disaster. I might wrong, but the issue did not exist on Windows 10. That trick only works when booting initially and the screen is stuck waiting for an Internet connection, but does not solve the No internet connection on Windows and other MS apps like Outlook not working. Only a full reboot solves this for a day or two until it comes back.
It's almost 2 years since I have the issue as well, and I don't expect Microsoft to fix it at this point.
It seems related to a Microsoft account log in or server check that fails or just can't connect to MS servers and then flags the entire operating systems as not having an Internet connection. Which is of course false and not true, like others reported here, Internet works fine.
Like others mentioned, Outlook.com emails don't work in Outlook, but email accounts from non Microsoft servers work fine. Microsoft Store complaints there is No internet, so does any other Office 365. Tray icon and control panel says no internet either. The Internet works fine. Rebooting the system works for a while until it happens again.