GreenMail and other NSU sites not loading when connected to VPN
Sometimes users are unable to load NSU sites, like GreenMail, when connected to the VPN. Follow the steps below to disable IPv6 and mitigate this issue.
1. First open "Network and Sharing Center" by right clicking on the network icon in the system tray and selecting "Open Network and Sharing Center."

2. After the "Network and Sharing Center" is open, select "Change adapter settings" on the right panel.

3. Right click on the adapter that is "Connected" and select "Properties."

4. Uncheck the box next to "Internet Protocol Version 6 (TCP/IPv6).

5. Test accessing the sites you were having issues with.