ลองตรวจสอบ hostname ดูครับ อาจไม่ถูกต้อง
ผมเช็ค hostname ใน ssh ตรงกับโดเมนนะครับ
logmail
postfix/smtp[15762]: connect to alt1.gmail-smtp-in.l.google.com[173.194.202.27]:25: Connection timed out
postfix/smtp[15762]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:400e:c00::1a]:25: Network is unreachable
postfix/smtp[15762]: connect to alt2.gmail-smtp-in.l.google.com[209.85.235.27]:25: Connection timed out
postfix/smtp[15762]: 5BF533F309: to=<
example@gmail.com>, relay=none, delay=20727, delays=20637/0.03/90/0, dsn=4.4.1, status=deferred (connect $
journal: plesk sendmail[15793]: Unable to get sender domain by sender mailname
journal: plesk sendmail[15793]: handlers_stderr: PASS
journal: plesk sendmail[15793]: PASS during call 'limit-out' handler
check-quota[15796]: Starting the check-quota filter...
journal: plesk sendmail[15793]: handlers_stderr: SKIP
journal: plesk sendmail[15793]: SKIP during call 'check-quota' handler
journal: plesk sendmail[15793]: Unable to get sender domain by sender mailname
postfix/pickup[14411]: 61B3242BB1: uid=10001 from=<example>
postfix/cleanup[14396]: 61B3242BB1: message-id=<
20170911152702.61B3242BB1@example.com>
postfix/qmgr[1699]: 61B3242BB1: from=<
example@example.com>, size=1048, nrcpt=1 (queue active)
postfix-local[15800]: postfix-local: from=example@example.com, to=example@example.com, dirname=/var/qmail/mailnames
dovecot: service=lda, user=example@example.com, ip=[]. msgid=<
20170911152702.61B3242BB1@example.com>: saved mail to INBOX
postfix/pipe[14431]: 61B3242BB1: to=<
example@example.com>, orig_to=<example>, relay=plesk_virtual, delay=0.11, delays=0.02/0/0/0.1, dsn$
postfix/qmgr[1699]: 61B3242BB1: removed
Host and Domain
