我在尝试设置 Postfix/Dovecot 以在我的 Ubuntu 服务器 15.10 上运行时遇到了这个问题。关注这指南尝试设置服务器，以前有效。但是，尝试升级到 15.10 需要我获得一台新服务器，因为安装中断了。现在，我再次遇到设置邮件的问题。
不确定到底是什么原因造成的，所以一些见解会很有帮助。谢谢！
我的文件如下：
邮件日志：
Jan 22 17:01:34 mail postfix/smtpd[5363]: connect from mta.iwsend.com[68.232.192.128]
Jan 22 17:01:34 mail postfix/smtpd[5363]: warning: SASL: Connect to private/auth failed: Connection refused
Jan 22 17:01:34 mail postfix/smtpd[5363]: fatal: no SASL authentication mechanisms
Jan 22 17:01:35 mail postfix/master[1169]: warning: process /usr/lib/postfix/smtpd pid 5363 exit status 1
Jan 22 17:01:35 mail postfix/master[1169]: warning: /usr/lib/postfix/smtpd: bad command startup -- throttling
Jan 22 17:02:35 mail postfix/smtpd[5385]: connect from mail175.suw14.mcdlv.net[198.2.183.175]
Jan 22 17:02:35 mail postfix/smtpd[5385]: warning: SASL: Connect to private/auth failed: Connection refused
Jan 22 17:02:35 mail postfix/smtpd[5385]: fatal: no SASL authentication mechanisms
Jan 22 17:02:36 mail postfix/master[1169]: warning: process /usr/lib/postfix/smtpd pid 5385 exit status 1
Jan 22 17:02:36 mail postfix/master[1169]: warning: /usr/lib/postfix/smtpd: bad command startup -- throttling
Jan 22 17:04:16 mail postfix/anvil[5365]: statistics: max connection rate 1/60s for (smtp:68.232.192.128) at Jan 22 17:01:34
Jan 22 17:04:16 mail postfix/anvil[5365]: statistics: max connection count 1 for (smtp:68.232.192.128) at Jan 22 17:01:34
Jan 22 17:04:16 mail postfix/anvil[5365]: statistics: max cache size 1 at Jan 22 17:01:34
Jan 22 17:06:01 mail postfix/master[1169]: terminating on signal 15
Jan 22 17:06:01 mail postfix/master[5572]: daemon started -- version 2.11.3, configuration /etc/postfix
邮件错误：
Jan 22 17:01:34 mail postfix/smtpd[5363]: fatal: no SASL authentication mechanisms
Jan 22 17:02:35 mail postfix/smtpd[5385]: fatal: no SASL authentication mechanisms
主配置文件
# TLS parameters
smtpd_tls_cert_file = /etc/ssl/certs/server.crt
smtpd_tls_key_file = /etc/ssl/private/server.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = mail.ebear.us
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = ebear.us, mail.ebear.us, localhost.ebear.us, localhost
relayhost =
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 104.236.240.12/32
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all
home_mailbox = Maildir/
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_sasl_local_domain =
smtpd_sasl_security_options = noanonymous
broken_sasl_auth_clients = yes
smtpd_sasl_auth_enable = yes
smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination
smtp_tls_security_level = may
smtpd_tls_security_level = may
smtp_tls_note_starttls_offer = yes
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
10-auth 具有 auth_mechanisms = plain
10-SSL：
ssl = yes
ssl_cert = </etc/dovecot/dovecot.pem
ssl_key = </etc/dovecot/private/dovecot.pem