DBMS_LDAP and ORA-12703

In case you are using the DBMS_LDAP package from a reasonable modern environment you may run into the error:

ORA-12703 this character set conversion is not supported

The simple solution to this is to run:

begin
  DBMS_LDAP.UTF8_CONVERSION := false;
end;
/

or if you are using SQL*Plus or SQL Developer, just:

exec DBMS_LDAP.UTF8_CONVERSION := false