NIS problem

[kpyau]

-    I am using redhat 7.3. -    My redhat 7.3 serve as a client to a 7.0 server in the LAN -    my server is the NIS server for my client -    problem is when i type in the password and username in my client      the x windows screen just flip once then put me back to the login screen      again.   -    What is the problem? is my nis client configure wrong?      i dont think so cause other 7.3 client working fine.       What is the problem actually? is it regarding the security?         Pls help!!!!!!!!!!!! thanks