Page 1 of 1

Problem with Mobile mail client STARTTLS port 587

Posted: Mon Sep 02, 2019 9:16 am
by zimico
Dear all,
My new server with centos 7, zimbra ose 8.8.15, we have 2 domains and use letsencrypt for both domains (following
Outlook on windows with TLS port 587 works OK. However, mail clients (gmai, bluemail,..) on android/iphone with STARTTLS port 587 does not work.
zimbra.log shows:

Code: Select all

Sep  2 15:57:29 sm01 postfix/submission/smtpd[10066]: connect from unknown[]
Sep  2 15:57:30 sm01 postfix/submission/smtpd[10066]: lost connection after AUTH from unknown[]

If I change from STARTTLS port 587 to SSL/TLS port 465, it's ok.
If I change from STARTTLS port 587 to STARTTLS port 587 (accept all certificate - email security not guaranteed), it's ok.
I'm appreciated if anybody can explain about those settings. Do we need to resetup letsencrypt cert?
I'm quite confuse about TLS port 587 on Outlook and STARTTLS port 587 on mobile client.
Best regards