My vpn user can no longer login, HELP PLEASE

I have a sbs 2003 box that I have inherited. I now have a user that can not login from home. The event viewer says :
“The user xx\userx connected from 71.180.xxx.x but failed an authentication attempt due to the following reason: Authentication was not successful because an unknown user name or incorrect password was used.”
Nothing has been changed on server since the user last login. User name and PW is correct.