Error 913: A Remote Access Client attempted to connect over a port that was reserved for Routers only (also re: Error 629 and 645). The event viewer may also generate the following event:
Event ID: 20188
Description: The user username, attempting to connect on port, was disconnected because of the following reason:
A Remote Access Client attempted to connect over a port that was reserved for Routers only.
1) Enable Remote access connections. To do this, go to Routing and Remote Access administrative tool>Ports>Properties, click the appropriate port (L2TP, Modem, PPTP, LPT1, and so on), and then click Configure, and then check the Remote access connections (inbound only).
2) Double-click the "Incoming Connections" icon on network connections folder and make sure "Allow VPN Connections" is enabled.