Jupyterhub & ldap

i’m doing a ground up installation on a dedicated server of TLJH under Ubuntu 20.04.1.
In april i#ve installed my last TLJH and the integration of LDAP worked fine, now im not able to authenticate. Error is:
ldap3.core.exceptions.LDAPStartTLSError: automatic start_tls befored bind not successful

i’ve found the discussion about the changes of LDAP3 but still i cant get it to work!

any help?