Merhabalar,
Bir sanal makinede Plesk 12.x kullanıyorum, mailler sürekli kuyrukta bekliyor. Bazı komut çıktıları aşağıdaki gibi postfix ya da qmail fark etmiyor sonuç aynı.

İlginiz için teşekkürler.

# tail -f /usr/local/psa/var/log/maillog                                                                                                                 Jan 10 01:16:05 server courier-pop3s: Connection, ip=[::ffff:37.140.190.61]
Jan 10 01:16:05 server courier-pop3s: LOGIN, user=destek@domain.com, ip=[:                                                                                        :ffff:37.xxx.xxx.61], port=[33282]
Jan 10 01:16:05 server courier-pop3s: LOGOUT, user=destek@domain.com, ip=[                                                                                        ::ffff:37.xxx.xxx.61], port=[33282], top=0, retr=0, rcvd=12, sent=843, time=0, s                                                                                        tls=1
Jan 10 01:18:52 server qmail: 1452381532.698312 delivery 1: deferral: Sorry,_I_w                                                                                        asn't_able_to_establish_an_SMTP_connection._(#4.4.1)/
Jan 10 01:18:52 server qmail: 1452381532.698337 status: local 0/10 remote 0/20
Jan 10 01:19:33 server qmail: 1452381573.722949 starting delivery 2: msg 1583185                                                                                         to remote sahin@xxx.com
Jan 10 01:19:33 server qmail: 1452381573.722970 status: local 0/10 remote 1/20
Jan 10 01:19:33 server qmail-remote-handlers[23035]: Handlers Filter before-remo                                                                                        te for qmail started ...
Jan 10 01:19:33 server qmail-remote-handlers[23035]: from=sahin@xxx.com
Jan 10 01:19:33 server qmail-remote-handlers[23035]: to=sahin@xxx.com
connect to mx.yandex.net[213.xxx.xxx.89]:25: Connection timed out
Jan  9 05:44:41 server postfix/smtp[10753]: F0F6B1408ED: to=<sahin@hoops.com>, relay=none, delay=728, delays=578/0.01/150/0, dsn=4.4.1, status=deferred (connect to mx.yandex.net[213.xxx.xxx.89]:25: Connection timed out)

# telnet localhost 25
Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 server.netbilgisayar.net ESMTP