Server Log say user authenticate but modem shows error 691

[amritap sinha]

 Dear All,
           I have try to implement  freeradius in RHCL 4 with my sql.
My data base connected to the   radius server properly and my radius
server authenticate the user properly inside the network and outside
the network. My problem is that when I try to connect any user through
dial up connection  my NAS and radius response and password
authenticate(basically I using CHAP password for authentication) but
modem shows error 691 in Windows XP O.S.
                     Please any one help me with  providing a suitable solution.


                         Thanks & Regards

                          Amritap Sinha