I noticed today that I can't connect to any websites if I enable the VPN option in Opera browser. If I connect directly to the Internet, there are no issues with surfing the Internet. I also can't connect to any other VPN.
I tried to troubleshoot the issues but ended up breaking my own Internet access.
1. I installed Windows and Opera on a VM and tried enabling VPN in Opera. There are no issues if I surf from the VM. I also installed other VPN software on the VM and connecting to them. No issues as well.
2. Googled around and tried various solutions. No joy.
3. Windows Diagnostics (whereby you right click on the network icon and select Troubleshoot problems) said there were DNS is not responding. I then set Google's DNS settings in Windows, still no joy.
4. Reset winsock (https://support.microsoft.com/en-us/kb/299357), restarted computer - no more Internet access.
5. Tethered my phone's connection to the computer - Internet works, but same issue remains: I still can't surf the Internet if I enable the VPN option in Opera. I can't connect to any VPN connections either. But it works very well in VM.
To summarize, I have two issues to be fixed:
1. A broken Internet access from resetting winsock
2. Resolve the lack of connectivity issue if VPN is enabled in Opera/connecting to VPN