MacOS Mojave unable to connect to Internet.

Since upgrading to MacOS Mojave, I am repeatedly losing access to the internet through both WiFi and Ethernet on both my MacBook Pro 15" (MacBookPro11,3) and my MacMini 2012.

In the Network settings, both Ethernet and Wi-Fi are connected.

This is not a DNS issue nor router issue - all other Macs and iPhones and iPads are able to connect to the internet. Only the Macs which are upgraded to MacOS Mojave are losing access to the internet.

Safari is unable to connect to the internet even if you give it a real IP address.

The Mac App Store, Mail, DropBox and other apps are unable to connect to the internet. The first clue to this problem is that DropBox's Icon in the MenuBar is GRAYED OUT.

I cannot connect to iCloud in System Preferences.

Weirdly, ONLY GOOGLE CHROME is able to connect to the internet. Everything else is unable to connect to the internet.

The only solution I found so far is to:

1. Delete the network services (both Wi-Fi and Ethernet).
2. Add the Ethernet and Wi-Fi services back.
3. RESET NV RAM by restarting the Mac while pressing the Command-Option-P-R Keys.

After doing this, everything can connect to the internet.

However, the problem returns after a few days.