nfs problem help

I am having problem mounting my nfs mount on my sun solaris 8 through automount using the automaster file. this has been working fine until today, when my workstation tries to mount the nfs
mount the following error is logged in /var/adm/message

NFS lookup failed for server comserv: error 7 (RPC: Authentication error)
NFS access failed for server comserv: error 7 (RPC: Authentication error)
NFS fsstat failed for server comserv: error 7 (RPC: Authentication error)

I tried mounting the nfs mount manually but this did not help.
I stopped and start nfs.client (lockd and statd)
this did not help either
I have also reboot my workstation but this did not
help either.

Nfs server and nis server are working fine because
I could log on to other workstart which also use
nfs mount and authenticate on nis

Can you help? please

Thanks in Advance

The first thing that I would expect is a problem on the server. It can export a filesystem to one workstation but not another. Check the exports on the server. The command for a Sun server is "share".

Thanks, the problem was the NFS server. I issued
/etc/init.d/nfs.server stop followed by
/etc/init.d/nfs.server start

and this solved the problem.