When computers both internally and remotely try to VPN into my server that is running Windows Server 2003 R2 Enterprise Edition, they receive VPN Error 800: The remote connection was not made because the attempted VPN tunnels failed.
Your windows Server 2003 R2 use to work 100% without any technical problems, and you have not changed any configuration settings on the server.
We noted that only 3 VPN clients were able to establish the VPN connection, the fourth connection was encountering the VPN Error 800:
We needed to increase the number of available ports for the client remote access / VPN users, by going to open the Routing and Remote Access console. It is under the Administrative Tools menu > Routing and Remote Access, expand the RAS – right click on ports and then select Properties.
Select the WAN Miniport (PPTP) entry and then select the Configure button at the bottom.
You can then change the number of ports to the maximum number of VPN users you will expect. For example in our environment we changed it to 20.
OK, OK again – Restart the Server.