A couple of days DSS was trown out of domain because of time difference.
OK, I corrected the time and re-joined DSS back to the domain.
After re-joining to the domain:
CONFIGURATION->NAS Resources->User Share Access (SMB/FTP/AFP) and
CONFIGURATION->NAS Resources->Group Share Access (SMB/FTP/AFP) lists
became empty and I had to re-enter all data there.
Strange. This is not very handy in my opinion. Can DSS keep those lists no matter
if it's joined to the domain?
When reconnecting to the ADS this should have automatically restored the users and groups. You can try to restore using the Import UIDs and GIDs in NAS Resources and the user information is stored in the test.log file from the log package that can be downloaded from Status > Hardware.