Issues with SAMBA - plz help

Hello.

We have 2 HP-UX machines in the same Domain with SAMBA installed and configured.

The problem is:
From my Windows PC when i try to reach "machine1" by using UNC:
\\machine1
I receive the window with all folders available :b:

From the same PC when i try to reach "mcahine2" by using UNC:
\\machine2
I receive a logon windows that asks for user & password. :confused:

Where is the setting/configuration that is responsible for this on machine2's smb.conf ?
It's not that i'm trying to reach a specific folder on machine2 that i don't have permissions for - but i only to view the list of directories.

Your help is appreciated.

Adija