[Samba] winbind use default domain problem after upgrade

[Perttu Aaltonen]

After upgrading a file server from Ubuntu 19.10 with Samba 4.10.5 to Ubuntu 20.04 with Samba 4.13.2, "winbind use default domain” doesn’t seem to work anymore.

I went through the release notes in between but nothing stood out for me that would require a configuration change.

Before the upgrade:
[2021/02/23 20:05:31.553745,  3] ../../auth/auth_log.c:629(log_authentication_event_human_readable)
  Auth: [SMB,(null)] user []\[user] at [Tue, 23 Feb 2021 20:05:31.553731 EET] with [NTLMv1] status [NT_STATUS_OK] workstation [192.168.0.11] remote host [ipv4:192.168.0.11:53784] became [DOMAIN]\[user] [SID redacted]. local host [ipv4:192.168.0.10:445] 

After the upgrade:
[2021/02/23 20:19:04.581131,  2] ../../auth/auth_log.c:635(log_authentication_event_human_readable)
  Auth: [SMB,(null)] user []\[user] at [Tue, 23 Feb 2021 20:19:04.581108 EET] with [NTLMv1] status [NT_STATUS_NO_SUCH_USER] workstation [192.168.0.11] remote host [ipv4:192.168.0.11:49792] mapped to []\[user]. local host [ipv4:192.168.0.12:445]

Do I need to change something in the configuration or have I hit some kind of bug?

Thanks!