How to add a user to a group in Active Directory using pl / sql?

To add a user to AD, I use the dbms_ldap package, the dbms_ldap.add_s procedure. Now I need to add a user to a specific group. Trying to add memberOf attribute:

 dbms_ldap.populate_mod_array( l_modarray, dbms_ldap.MOD_ADD, 'memberOf', ldap_helper.to_strcol('CN='||GroupName||',OU=User Accounts,DC='host',DC=test')); 

but it gives an error. I tried to make dbms_ldap.modify_s the group itself, but I also get an error.