我在 Ubuntu 20.04 上使用最新版本的 DKIM + Postfix 我得到了 DKIM 来签署电子邮件 user@smtpmail.mydoamin.com。然而，它拒绝签署来自@mydomain.com 的电子邮件。是否可以为两个电子邮件地址签名，如果可以，我该怎么做？
下面是我的 opendkim.conf
# This is a basic configuration that can easily be adapted to suit a standard
# installation. For more advanced options, see opendkim.conf(5) and/or
# /usr/share/doc/opendkim/examples/opendkim.conf.sample.
# Log to syslog
Syslog yes
# Added later
SyslogSuccess Yes
LogWhy Yes
# Required to use local socket with MTAs that access the socket as a non-
# privileged user (e.g. Postfix)
UMask 007
# Sign for example.com with key in /etc/dkimkeys/dkim.key using
# selector '2007' (e.g. 2007._domainkey.example.com)
Domain smtpmail.rapidseohost.com
KeyFile /etc/dkimkeys/smtpmail.private
Selector smtpmail
# Commonly-used options; the commented-out versions show the defaults.
Canonicalization relaxed/simple
#Mode sv
SubDomains yes
# Socket smtp://localhost
#
# ## Socket socketspec
# ##
# ## Names the socket where this filter should listen for milter connections
# ## from the MTA. Required. Should be in one of these forms:
# ##
# ## inet:port@address to listen on a specific interface
# ## inet:port to listen on all interfaces
# ## local:/path/to/socket to listen on a UNIX domain socket
#
Socket inet:8891@localhost
#Socket local:/run/opendkim/opendkim.sock
## PidFile filename
### default (none)
###
### Name of the file where the filter should write its pid before beginning
### normal operations.
#
PidFile /run/opendkim/opendkim.pid
# Always oversign From (sign using actual From and a null From to prevent
# malicious signatures header fields (From and/or others) between the signer
# and the verifier. From is oversigned by default in the Debian pacakge
# because it is often the identity key used by reputation systems and thus
# somewhat security sensitive.
OversignHeaders From
## ResolverConfiguration filename
## default (none)
##
## Specifies a configuration file to be passed to the Unbound library that
## performs DNS queries applying the DNSSEC protocol. See the Unbound
## documentation at http://unbound.net for the expected content of this file.
## The results of using this and the TrustAnchorFile setting at the same
## time are undefined.
## In Debian, /etc/unbound/unbound.conf is shipped as part of the Suggested
## unbound package
# ResolverConfiguration /etc/unbound/unbound.conf
## TrustAnchorFile filename
## default (none)
##
## Specifies a file from which trust anchor data should be read when doing
## DNS queries and applying the DNSSEC protocol. See the Unbound documentation
## at http://unbound.net for the expected format of this file.
TrustAnchorFile /usr/share/dns/root.key
## Userid userid
### default (none)
###
### Change to user "userid" before starting normal operation? May include
### a group ID as well, separated from the userid by a colon.
#
UserID opendkim
