Are you getting an error on windows client like this "The specified network password is not correct."?
Then you may not have usermapping for those domain users.
CLI command to check this is
"wcc -s domain\username."
If it says user not mapped, you may need to add unix user entries in /etc/passwd or ldap or nis. Then create usermapping via /etc/usermap.cfg. Verify /etc/nsswitch.conf to make sure that passwd entries are looked at the correct sources.
or you may need to check "options wafl.default_unix_user". Set it to some user default user like 'pcuser' in /etc/passwd.