TS3400D with 4x2Tproblem with restricted access

[eng_HK]

Hi All
I have a new TS3400D, before start to configure it I made the upgrade firmware to 1.20-0.11 the latest firmware.
I have configured it with 3 Disk in raid 5 and 1 spare, dynamic link aggregation and joined to my active directory domain.

I defined 11 folder to share, with SMD hidden option enabled and for some also the recycle bin.
If I not enalbe the restriction for the folders, using group because I need it, eveything works fine I can access the folders, also hidden and no problems.
As soon as I enalbe for example 1 folder the restriction for the access and set the permissions to the group I need when I try to reach the folder the TS asked always for user and password. The problem is that the users that I'm using to access to make test is the admin of the domain and of course is inside the group.
I thinked that the problem could be the nested group so I decide to create a test group with the only administrator inside, but again the same problem,

I decided to wrote in the forum because I have another TS3400 with the SAME configuration with the restrction enabled and with permission on folder and evrything works fine.

The only difference beetwen the 2 nas is that the "old" was configured before the upgrade of the firmware, the new is configured after the upgrade.

Please help me because I becoming crazy..

Thanks