OpenDKIM 无法启动：“opendkim：必须指定 milter 套接字”

我正在尝试使用 postfix、dovecot、amavis 和 opendkim 来设置服务器进行签名。

OpenDKIM 不会启动，这是journalctl -xe停止并启动 opendkim 后的输出：

Jul 21 21:54:17 mail systemd[1]: Starting OpenDKIM DomainKeys Identified Mail (DKIM) Milter...
-- Subject: A start job for unit opendkim.service has begun execution
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- A start job for unit opendkim.service has begun execution.
--
-- The job identifier is 54385.
Jul 21 21:54:17 mail opendkim[108677]: opendkim: milter socket must be specified
Jul 21 21:54:17 mail systemd[1]: opendkim.service: Control process exited, code=exited, status=78/CONFIG
-- Subject: Unit process exited
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- An ExecStart= process belonging to unit opendkim.service has exited.
--
-- The process' exit code is 'exited' and its exit status is 78.
Jul 21 21:54:17 mail systemd[1]: opendkim.service: Failed with result 'exit-code'.
-- Subject: Unit failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- The unit opendkim.service has entered the 'failed' state with result 'exit-code'.

我的 OpenDKIM (/etc/opendkim.conf) 配置如下所示：

Syslog              yes
LogResults          yes
LogWhy              yes
SyslogSuccess       yes
UMask               002
Canonicalization    relaxed/relaxed

# Only sign, don't verify (Amavis takes care of the verification)
Mode                s

KeyTable            /etc/opendkim/keytable
SigningTable        refile:/etc/opendkim/signingtable

正如您在配置中看到的，我只希望 OpenDKIM 签名，而不是验证。