Smbstatus does not resolve anymore the usernames

Hi, smbstatus, on UCSDC, no longer shows the usernames but only numeric ids:

Samba version 4.10.1-Univention
PID     Username     Group        Machine                                   Protocol Version  Encryption           Signing       
----------------------------------------------------------------------------------------------------------------------------------------
31976   3000981      3000012      172.20.0.12 (ipv4:172.20.0.12:1173)       NT1               -                    HMAC-MD5      

there is no errors at all. On the slave and on the backup it works.

# lsb_release -a
No LSB modules are available.
Distributor ID: Univention
Description:    Univention Corporate Server 4.4-4 errata642 (Blumenthal)
Release:        4.4-4 errata642
Codename:       Blumenthal