[exim] discard mail from all local users except

Dear Colleagues,

I'm trying to discard mails from all local users (shared hosting) other
than from root and maybe a few others. I've configured

acl_not_smtp = acl_not_smtp
begin acl

acl_not_smtp:
     accept condition           = ${if bool{${lookup{$authenticated_sender}lsearch{/etc/mail/whitelist.local}}}}
     discard message             = Local sending is prohibited

$ cat /etc/mail/whitelist.local
root
root@???

For some reason the accept part does not work, mail from the local root
is discarded too. What's wrong with my lookup?
Here is the debug:
https://termbin.com/kavi (the real domain is hidden as "hiddendomain").

I've tried replacing $authenticated_sender with $sender_ident with no result.

I'm talking about sending via exim as /usr/sbin/sendmail, not about SMTP
to localhost.


--
Victor Sudakov VAS4-RIPE
http://vas.tomsk.ru/
2:5005/49@fidonet