Hi, I had to revert my samba DC after upgrade to 4.15. win7 and win2008srv R2 have problems login, win10 and linux clients seems to works fine. There are more reports about this problem on samba mailing list [1]. Consider locking samba to latest 4.14 if doing upgrade of DC. Regards, Łukasz [1] https://lists.samba.org/archive/samba/2021-October/237566.html