Exim is spitting out (what looks like) a privilege error:
# tail -n1 /var/log/exim/paniclog
2021-11-15 16:38:35.955 [682275] 1mme43-002rUN-QV unable to open file for reading: /etc/opendkim/keys/xxxxxxxxx.com/mail.private
despite the fact it looks as though Exim should be able to read the file
# namei -mo /etc/opendkim/keys/xxxxxxxxx.com/mail.private
f: /etc/opendkim/keys/xxxxxxxxx.com/mail.private
drwxr-xr-x root root /
drwxr-xr-x root root etc
drwxr-x--- opendkim mail opendkim
drwxr-x--- opendkim mail keys
drwxr-x--- opendkim mail xxxxxxxxx.com
-rw-r----- opendkim mail mail.private
$ groups exim
mail dovecot opendkim privkey exim
Thanks in advance.