I found my issue. The openvpn_plugin group only shows within the OpenVPN tool page in ClearOS. It won't show in the standard group section. When you go to the OpenVPN plugin page in ClearOS, you'll be able to see what users are part of that group by clicking on View Members App Policies of the OpenVPN page. Don't be alarmed if you see all AD users in there. Even though you see all AD users, if you go back to Users in ClearOS and view the actual user, you'll notice that the users you added to the openvpn_plugin group are the only ones that will show as users with access while any user you didn't will show the user DOES NOT have access.