VPN: Error is"The VPN connection failed due to unsuccessful domain name resolution"

This error can happen when people use Google Public DNS (DNS servers 8.8.8.8 and 8.8.4.4) or any other DNS server which has been manually input in their network settings. The remedy is to eliminate the static DNS servers and let the computer/device get the correct DNS server that is appropriate for the system they're currently on.

Here is how to do it on a PC:

Choose the Start button and then select the Control Panel.
Beneath the Network and Internet class, Pick the Network and Sharing Center.
From the left-hand panel select Change Adapter Settings.
Click Change adapter configurations located on the left column header.
Pick your system adapter, right-click and select Properties.
Emphasize Internet Protocol Version (TCP/IPv4) and Click Properties.

Here is how to get it done on a Mac:

Click the Apple menu and choose System Preferences.
Double-click on the Network icon.
Visit the TCP/IP tab, and then highlight any DNS server IP address you see here.
Choose the - icon at the bottom left to remove it.
Apply your settings by clicking OK, and click Employ on the next screen to shut the window.