Code:

root@bh-dc:~# cat /etc/issue.net
Debian GNU/Linux 9
root@bh-dc:~# uname -a
Linux bh-dc 4.9.0-4-amd64 #1 SMP Debian 4.9.51-1 (2017-09-28) x86_64 GNU/Linux
root@bh-dc:~# samba -V
Version 4.5.12-Debian
root@bh-dc:~# tail -n 100 /var/log/samba/log.samba
  task_server_terminate: [cldapd failed to open samdb]
[2020/06/30 00:45:35.995740,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [ntp_signd failed to open samdb]
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
[2020/06/30 00:45:35.998616,  0] ../source4/smbd/server.c:211(samba_terminate)
  samba_terminate of 390: nbtd failed to open samdb
[2020/06/30 00:45:36.000015,  0] ../source4/smbd/server.c:211(samba_terminate)
  samba_terminate of 395: dreplsrv: Failed to connect to local samdb: WERR_DS_UNAVAILABLE

[2020/06/30 00:45:36.001917,  0] ../source4/smbd/server.c:211(samba_terminate)
  samba_terminate of 394: kdc: krb5_init_context samdb connect failed
[2020/06/30 00:45:36.002692,  0] ../source4/smbd/server.c:211(samba_terminate)
  samba_terminate of 393: cldapd failed to open samdb
[2020/06/30 00:45:36.005688,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [dnsupdate: Failed to connect to local samdb
  ]
[2020/06/30 00:45:36.008348,  0] ../source4/smbd/server.c:211(samba_terminate)
  samba_terminate of 397: ntp_signd failed to open samdb
  task_server_terminate: [kccsrv: Failed to connect to local samdb: WERR_DS_UNAVAILABLE
  ]
[2020/06/30 00:45:36.035051,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [dns: samdb_connect failed]
[2020/06/30 00:45:36.293450,  0] ../file_server/file_server.c:46(file_server_smbd_done)
  file_server smbd daemon died with exit status 1
[2020/06/30 00:45:36.293501,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [smbd child process exited]
[2020/06/30 00:45:36.324410,  0] ../source4/winbind/winbindd.c:49(winbindd_done)
  winbindd daemon exited normally
[2020/06/30 00:45:36.324450,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [winbindd child process exited]
[2020/06/30 00:45:36.635904,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [Failed to startup ldap server task]
[2020/06/30 21:26:23.774691,  0] ../source4/smbd/server.c:115(sig_term)
  SIGTERM: killing children
[2020/06/30 21:26:23.774730,  0] ../source4/smbd/server.c:120(sig_term)
  Exiting pid 387 on SIGTERM
[2020/06/30 21:26:23.775809,  0] ../source4/smbd/server.c:120(sig_term)
  Exiting pid 391 on SIGTERM
[2020/06/30 21:26:23.777643,  0] ../source4/smbd/server.c:120(sig_term)
  Exiting pid 389 on SIGTERM
[2020/06/30 21:26:17.878529,  0] ../source4/smbd/server.c:372(binary_smbd_main)
  samba version 4.5.12-Debian started.
  Copyright Andrew Tridgell and the Samba Team 1992-2016
[2020/06/30 21:26:18.013758,  0] ../source4/smbd/server.c:479(binary_smbd_main)
  samba: using 'standard' process model
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
[2020/06/30 21:26:18.032541,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
[2020/06/30 21:26:18.052337,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
[2020/06/30 21:26:18.056346,  0] ../lib/util/become_daemon.c:124(daemon_ready)
  STATUS=daemon 'samba' finished starting up and ready to serve connections
  task_server_terminate: [nbtd failed to open samdb]
[2020/06/30 21:26:18.060196,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
[2020/06/30 21:26:18.062659,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
[2020/06/30 21:26:18.063273,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [dreplsrv: Failed to connect to local samdb: WERR_DS_UNAVAILABLE
  ]
  task_server_terminate: [kdc: krb5_init_context samdb connect failed]
  task_server_terminate: [cldapd failed to open samdb]
[2020/06/30 21:26:18.070222,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [ntp_signd failed to open samdb]
[2020/06/30 21:26:18.070830,  0] ../source4/smbd/server.c:211(samba_terminate)
  samba_terminate of 386: ntp_signd failed to open samdb
[2020/06/30 21:26:18.072679,  0] ../source4/smbd/server.c:211(samba_terminate)
  samba_terminate of 379: nbtd failed to open samdb
[2020/06/30 21:26:18.073435,  0] ../source4/smbd/server.c:211(samba_terminate)
  samba_terminate of 383: kdc: krb5_init_context samdb connect failed
[2020/06/30 21:26:18.074155,  0] ../source4/smbd/server.c:211(samba_terminate)
  samba_terminate of 384: dreplsrv: Failed to connect to local samdb: WERR_DS_UNAVAILABLE

[2020/06/30 21:26:18.075127,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [kccsrv: Failed to connect to local samdb: WERR_DS_UNAVAILABLE
  ]
[2020/06/30 21:26:18.075799,  0] ../source4/smbd/server.c:211(samba_terminate)
  samba_terminate of 382: cldapd failed to open samdb
  task_server_terminate: [dnsupdate: Failed to connect to local samdb
  ]
samba: setproctitle not initialized, please either call setproctitle_init() or link against libbsd-ctor.
[2020/06/30 21:26:18.106508,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [dns: samdb_connect failed]
[2020/06/30 21:26:18.380770,  0] ../file_server/file_server.c:46(file_server_smbd_done)
  file_server smbd daemon died with exit status 1
[2020/06/30 21:26:18.380823,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [smbd child process exited]
[2020/06/30 21:26:18.406434,  0] ../source4/winbind/winbindd.c:49(winbindd_done)
  winbindd daemon exited normally
[2020/06/30 21:26:18.406473,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [winbindd child process exited]
[2020/06/30 21:26:18.751500,  0] ../source4/smbd/service_task.c:35(task_server_terminate)
  task_server_terminate: [Failed to startup ldap server task]
root@bh-dc:~# samba-tool dbcheck
Invalid flag combination 0x3 for 'aCSIdentityName' in @ATTRIBUTES
Failed to connect to 'tdb:///var/lib/samba/private/sam.ldb' with backend 'tdb': Unable to load ltdb cache records of tdb '/var/lib/samba/private/sam.ldb'
ERROR: Failed to connect to DB at None.  If this is a really old sam.ldb (before alpha9), then try again with --force-modules