Exim dovecot2 debian8. Access error?

Question

Debian

Transferred the mail server from bsd to debian, but for some reason an error occurs when delivering mail, i.e. exim cannot put new mail in the folder created by dovecot
Permission denied: cannot chdir to /var/mail/domain.ru/[email protected]/
Transport:

dovecot_delivery:
     driver = appendfile
     maildir_format = true
     directory = /var/spool/mail/$domain/[email protected]$domain
     create_directory = true
     directory_mode = 0770
     mode_fail_narrower = false
     message_prefix =
     message_suffix =
     delivery_date_add
     envelope_to_add
     return_path_add
     user = mail
     group = mail
     mode = 0660

dovecot and exim run as a single user - mail.
P/s/ /var/spool/mail/ symlink to /var/mail/

Answer 1

who is the owner and what rights does the /var/mail/ folder have?