to get connection to VPN server

dear sir,
i am using ME operating system. i make a new connection(from network and dial-up connection) to vpn server using vpn adapter. first time, i can get connection to vpn server. but later i can't get connection. so, i delete this connection and make a new connection. first time is ok and later can't get connection.so, please help me and tell me the way to solve the problem.

thanks,
lynn