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

This error can occur when people use Google Public DNS (DNS servers 8.8.8.8 and 8.8.4.4) or any other DNS server that was manually entered in their network settings. The solution is to remove the static DNS servers and let the computer/device obtain the correct DNS server that is appropriate for the network they are currently on.

Here's how to do it on a PC:

1. Select the Start button and then select the Control Panel.
2. Under the Network and Internet category, select the Network and Sharing Center. 
3. In the left-hand panel select Change Adapter Settings. 
4. Click on Change adapter settings located on the left column header.
5. Choose your network adapter, right click and choose Properties.
6. Highlight Internet Protocol Version (TCP/IPv4) and click on Properties.
7. Select Obtain DNS server address automatically. 
8. Click OK.

Here's how to do it on a Mac:

1. Click on the Apple menu and choose System Preferences.
2. Double-Click on the Network icon.
3. Select the Wi-Fi (or Ethernet) adapter on the left and then select Advanced... in the bottom right.
4. Go to the TCP/IP tab, and then highlight any DNS server IP address you see here.
5. Select the - icon in the bottom left to remove it.
6. Apply your settings by clicking OK, and then click Apply on the next screen to close the window.