Problem with Mobile mail client STARTTLS port 587

Discuss your pilot or production implementation with other Zimbra admins or our engineers.
Post Reply
User avatar
zimico
Outstanding Member
Outstanding Member
Posts: 225
Joined: Mon Nov 14, 2016 8:03 am
Location: Vietnam
ZCS/ZD Version: 8.8.15 P3
Contact:

Problem with Mobile mail client STARTTLS port 587

Post 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 https://github.com/VojtechMyslivec/letsencrypt-zimbra/)
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[27.3.33.139]
Sep  2 15:57:30 sm01 postfix/submission/smtpd[10066]: lost connection after AUTH from unknown[27.3.33.139]
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
Minh.
Post Reply