Access denied

why do I have an “access denied” ?

1. I add an NT 4 WST client to the domain with SRVMGR.

2. after rebooting the client we do a login on local (because the host is now member of the domain)

3. I try to map a shared folder from the fileserver and it succeed, but as sun as I want to open the new maped folder, I receive
“access denied”.

The user is member of the “global group” who has change rights, the login is the same for the domain and the local login.

If the user try to login from an other NT WST
is it working perfectly.

Thanks for your help
Ruedi