The problem we encountered was a Windows 10 PC which connected to a wifi access point successfully but did not have any internet access.
Using a command prompt and entering ipconfig /release we got this error message:
An error occurred while releasing interface Wi-Fi : The RPC server is unavailable.
The fix was:
Go to control panel -> administrative tools -> double click on services
click on DHCP client (which was stopped) and click start
After a short time the PC obtained an IP address from a DHCP server and the internet was reachable.
For some reason the DHCP client was stopped even though the PC has been rebooted twice.