cant set password for user

hi everybody

i cant set password for user (jam)

i tried to

#passwd jam
enter newpasswd :

after enter it showing

passwd : cannot get default domain:internal yp server or client error

i also check cat /etc/shadow file

jam:*:LK*:........
 

user is locked ... and i trying to unlock using

#passwd -u jam..
 

it showing

illegal option --u 

plz help me anyone face this issue before ....

try

#pwconv
#passwd jam

Hi ayman..
i tried #pwconv
there is no luck ... still it showing cant get default domain : internal yp server or client error

What says:

grep "^passwd:" /etc/nsswitch.conf

?

i solved ..
it is on NIS