If PC can't connect to the internet, and you can see the following screenshot, it shows blank properties when clicking the details button.
Perform the following steps to check if it is caused by Zpfilter. Click the Properties button and un-select "Zentera Packet Filter Driver" and click "OK"
If the connection is back, it means the issue is caused by Zpfilter Driver.
Perform the following steps to completely uninstall CoIP/Zpfilter and reinstall CoIP/Zpfilter.
Uninstall "CoIP Network Service" from "Applications and Features"
Open CMD as Administrator and type to see if Zpfilter is installed
netcfg -v -s n | findstr nt_zpfilter
nt_zpfilter Zentera Packet Filter Driver
Command to uninstall Zpfilter driver
netcfg.exe -v -u nt_zpfilter
Reboot and reinstall CoIP network service