Impossible samba join

Hi, I’m tryng to join a member server (samba and cups via samba) into domain.
Ucs DC 5.0.5 and Ucs member 5.0.5, this is join output error:

Configure 26univention-samba.inst Fri Oct  6 16:24:44 CEST 2023
2023-10-06 16:24:44.618533830+02:00 (in joinscript_init)
ERROR: It is not possible to install a samba 3 domaincontroller 
       into a samba 4 environment.

How can I fix it?
Thank you

I am having the same problem.