There are multiple reports of Windows update not being able to connect to the Update server and other Microsoft services not being able to connect to the Internet. While this is being investigated, you can try changing the DNS and see if it resolves the issue for you.
To change the DNS, perform the following steps:
- Press Windows key+R to open Run dialog box.
- Type in ncpa.cpl and press Enter.
- Right-click the device in the Network list through which you connect and choose Properties.
- Select Internet Protocol version 4 and choose properties just below the Checkbox list.
- Select the radio button "Use the following DNS servers" and add the following values in the boxes:
8.8.8.8
8.8.4.4 6. Press OK and Reboot your computer.
[Update 2/1/19]
The issue has started to correct for those who are affected. It is expected to be fully fixed in the next 24 hours or so.
[Added 2/5/19:]
You can try restarting the network router simply which should refresh the things if you do not want to change DNS in Windows.