VPN SBS 2003 stopped working

I’m setting up my first server. Using SBS 2003. I established VPN connection yesterday, and earlier today. No problem. But then I quickly tried to connect the VPN 3 or 4 times in about 1 minute. Now it won’t let me connect. It times out. I’m thinking it needs something reset, but don’t know where to look. My user account is not locked out. I am able to establish VPN with a similar laptop working through the same home router, using the same username/pw. It just doesn’t like this one machine. I have removed Norton from the client. No change. I have shut off windows firewall on the client, no change.