Incoming Connections

I have 2 XP Pro PCs. One is part of a domain and is
configured for incoming connections.

When I dial in I can handshake with the modem but get the
error "691 the username or password are not valid on the
domain"
I have tried the local machine name for domain,the domain
name and left it blank. I have checked and changed
username and password. I have also double checked
authentication and tried both unsecure and secure. The
users have permissions to dial in on the pc and on the
domain controller. The users also have local permissions
to remote control the pc

Any Ideas?