ypserv refused connect problems passwd.adjunct map

Dear All,

I am getting lots of the following error messge on a slave nis Linux
server lately, the only thing that was changed was the implementing of
the passwd.adjunct.byname on the NIS master (solaris 9)

ypserv[11225]: refused connect from 10.8.208.85:34346 to procedure
ypproc_match (nis_domain,passwd.adjunct.byname;-1)

there is nscd daemon is disabled restarting the services such as
ypservr, portmap did not reslove the issue, checking the sevice using
rpcinfo -u nisslave servicename does not report any obvious problems
from any clients involved.

how would one go about troubleshooting such an issue, and resolving
it, the main subsystme involved i guess are the portmapper, ypserv,
and nscd on the server side, and ypbind, and portmapper, and nscd on
the client side, the clients, and servers are all RHEL 3.0

nscd was disabled to narrow the problem, and still we get this message.

TIA, and regards,

Walid