The server cannot open ports on the router. Ensure that ports 80, 443, 987 are opened and pointed the IP address on the server. If you are using e-mail open port 25, and if you are using VPN, open port 1723.
SBS 2003 Port Forwarding: 80, 443 Web and SSL
4125 – Remote Web Workplace
1723 GRE – VPN