Problem:
You need to install or reinstall administrative templates for GPOs
Solution:
copy the ADMX files to
/var/lib/samba/sysvol/<domainname>/Policies/PolicyDefinition
the adml files needs to be placed in
/var/lib/samba/sysvol/<domainname>/Policies/PolicyDefinition/de-DE
/var/lib/samba/sysvol/<domainname>/Policies/PolicyDefinition/en-US
It might be necessary to check and reset the sysvol:
samba-tool ntacl sysvolcheck → Check sysvol ACLs match defaults (including correct ACLs on GPOs).
samba-tool ntacl sysvolreset→ Reset sysvol ACLs to defaults (including correct ACLs on GPOs).