Ubuntu 20.04 + Virtualmin环境下Procmail无法写入$HOME/Maildir的问题求助

各位好，我一整天都在网上找解决办法，就是搞不定Procmail无法写入用户$HOME/Maildir目录的问题。我用Virtualmin管理我的Ubuntu 20.04服务器，下面是我的Procmail配置和错误日志，麻烦帮忙排查下问题出在哪！

我的Procmailrc配置 #

LOGFILE=/var/log/procmail.log
TRAP=/etc/webmin/virtual-server/procmail-logger.pl
:0wi
VIRTUALMIN=|/etc/webmin/virtual-server/lookup-domain.pl --exitcode 73 $LOGNAME
EXITCODE=$?
:0
* ?/bin/test "$EXITCODE" = "73"
/dev/null
EXITCODE=0
:0
* ?/bin/test "$VIRTUALMIN" != ""
{
INCLUDERC=/etc/webmin/virtual-server/procmail/$VIRTUALMIN
}
ORGMAIL=$HOME/Maildir/
DEFAULT=$HOME/Maildir/
DROPPRIVS=yes

错误日志内容 #

日志里反复出现这类错误：

Insecure dependency in exec while running with -T switch at /etc/webmin/virtual-server/lookup-domain.pl line 19.
procmail: Program failure (255) of "/etc/webmin/virtual-server/lookup-domain.pl"
procmail: Unable to treat as directory "/home/xxxx/Maildir"

备注：内容来源于stack exchange，提问作者user1142052