Dovecot“無法載入 SSL 證書”

我花了很多時間試圖讓 Dovecot 工作。嘗試連接時，它不斷拋出以下消息：

May 15 02:55:20 yoshi128k dovecot: imap-login: Error: Failed to initialize SSL server context: Can't load SSL certificate: error:14187180:SSL routines:ssl_do_config:bad value: section=system_default
May 15 02:55:20 yoshi128k dovecot: imap-login: Disconnected: TLS initialization failed. (no auth attempts in 0 secs)

這是 doveconf -n 的輸出：

# 2.3.4.1 (f79e8e7e4): /etc/dovecot/dovecot.conf
# Pigeonhole version 0.5.4 ()
doveconf: Warning: NOTE: You can get a new clean config file with: doveconf -Pn > dovecot-new.conf
doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:25: 'imaps' protocol is no longer necessary, remove it
doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:25: 'pop3s' protocol is no longer necessary, remove it
# OS: Linux 4.19.0-16-amd64 x86_64 Debian 10.9 ext4
# Hostname: yoshi128k.mooo.com
auth_mechanisms = plain login
disable_plaintext_auth = no
mail_location = maildir:/var/mail/vhosts/%d/%n/
mail_privileged_group = mail
namespace inbox {
 inbox = yes
 location =
 mailbox Drafts {
   special_use = \Drafts
 }
 mailbox Junk {
   special_use = \Junk
 }
 mailbox Sent {
   special_use = \Sent
 }
 mailbox "Sent Messages" {
   special_use = \Sent
 }
 mailbox Trash {
   special_use = \Trash
 }
 prefix =
}
passdb {
 driver = pam
}
passdb {
 args = /etc/dovecot/dovecot-sql.conf.ext
 driver = sql
}
postmaster_address = postmaster at yoshi128k.tk
protocols = imap pop3 lmtp
service auth-worker {
 user = vmail
}
service auth {
 unix_listener /var/spool/postfix/private/auth {
   group = postfix
   mode = 0660
   user = postfix
 }
 unix_listener auth-userdb {
   group = postfix
   mode = 0660
   user = postfix
 }
 user = dovecot
}
service imap-login {
 inet_listener imap {
   port = 143
 }
 inet_listener imaps {
   port = 993
   ssl = yes
 }
}
service lmtp {
 unix_listener /var/spool/postfix/private/dovecot-lmtp {
   group = postfix
   mode = 0600
   user = postfix
 }
}
service pop3-login {
 inet_listener pop3 {
   port = 110
 }
 inet_listener pop3s {
   port = 995
   ssl = yes
 }
}
ssl_cert = </etc/ssl/certs/dovecot.crt
ssl_client_ca_dir = /etc/ssl/certs
ssl_dh = # hidden, use -P to show it
ssl_key = # hidden, use -P to show it
ssl_key_password = # hidden, use -P to show it
ssl_min_protocol = SSLv3
userdb {
 driver = passwd
}
userdb {
 args = uid=vmail gid=vmail home=/var/mail/vhosts/%d/%n
 driver = static
}

我確實有 10-ssl.conf 指向我的證書文件，所以我不太確定發生了什麼。

編輯：這是 OpenSSL 的 s_client 的輸出：

root@yoshi128k:/etc/postfix# openssl s_client -connect mail.yoshi128k.tk:143 -starttls imap
CONNECTED(00000003)
139987247760512:error:1408F10B:SSL routines:ssl3_get_record:wrong version number:../ssl/record/ssl3_record.c:332:
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 345 bytes and written 345 bytes
Verification: OK
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
Early data was not sent
Verify return code: 0 (ok)
---

顯然，問題一直是 openssl.cnf 中的無效條目

引用自：https://serverfault.com/questions/1063626