DKIM signature is not put (Exim+Centos 6) where to look for the reason?

Question

Exim

Exim stubbornly refuses to sign emails.
The keys are generated, Exim has access to them, the domain entry is registered and the check on dkimcore.org/tools/keycheck.html passes, but there is no signature in the message header.
Where to look for ends?
Exim config piece here

begin transports
DKIM_DOMAIN = mydomain.ru
DKIM_FILE = /var/vmail/dkim/mail.private #Exim has access here
DKIM_PRIVATE_KEY = ${if exists{DKIM_FILE}{DKIM_FILE}{0}}
DKIM_CANON = relaxed
remote_smtp:
driver = smtp
dkim_domain = DKIM_DOMAIN
dkim_selector = mail # is the selector we chose.
dkim_private_key = DKIM_PRIVATE_KEY
dkim_canon = relaxed
dkim_strict = yes
dovecot_delivery:
driver = pipe

Answer 1

Understood.
Two mistakes:
doesn't work, you just need to replace it with the path+filename
here the real
exim bomb pulls everything into the header including what is written after the hash mark, the result in the header
and signature verification fails