First of all i’m “old” openSUSE user… since version 12.x… 
After trying a lot of distributions, i choose openSUSE because of great integration with Active Directory Domain.
At work we have Windows environment… Windows Server with Active Directory Domain and about 500 computers.
Since version 12.x i’m using Windows Domain Membership and it works great every time… until Samba 4.15.x version…
On new laptop i installed latest TW version which came with 4.15.x samba version… after installing everything i tried join domain but without success.
I have written tutorial by myself how to join domain:
Install samba, samba-winbind, krb5-client
Enable samba and samba client in firewall
In apparmor set to complain smbd, nmbd, winbind
Edit network setting: add domain server ip address and domain name
At last start Windows Domain Membership and join domain, but always get this message:
Cannot use the workgroup COMPANY.DOMAIN for linux authentication
Enter a domain or disable using SMB for Linux authentication.
Luckly, i had snapshot openSUSE-Tumbleweed-DVD-x86_64-Snapshot20210712-Media which came with 4.14.5 Samba version.
Install it from zero, disable online repositories, installed everything like in my tutorial and voila… Domain Joined.
After upgrading to Samba 4.15.x, and trying to Leave and Join Domain, same error.
So i installed everything again with 4.14 version, and lock all samba packages in Yast to version 4.14.5.
On internet i didn’t find any solutions.
Problem is definitely in samba 4.15 because with older version everything worked great.
Is there any suggestion what to do?
I have one Virtual Machine where i testing Domian Join, but it works only with Samba 4.14.