Hi, I have exhausted my limited knowledge in trying to resolve this apparently common problem, I found no solution searching Internet so I decided to ask for some help. HJope someone can shed some light I defined a Mail server pretty much following the The Perfect Server - Ubuntu 18.04 tutorial. My objective is be able to connect to my server from Outlook client among others. All DNS definitions etc are fine, Roundcube mail accounts work fine and so far I have been able to define both IMAP and POP3 connections from Gmail and Android Samsung mail so I guess my configuration is basically fine. However when I try to define an IMAP connection from Outlook client I am not able to connect: the connection fails. POP3 accounts work fine from Outlook. Following is the mail.log output when I try to connect from Android Outlook client (Iit also fails from Outlook 2019 in Win10 PC). Any help is greatly appretiated. <code> Mar 28 20:56:44 mail postfix/submission/smtpd[10513]: connect from unknown[52.125.136.0] Mar 28 20:56:44 mail dovecot: imap-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=52.125.136.0, lip=96.30.197.163, TLS: Disconnected, session=<iBiddPChQFk0fYgA> Mar 28 20:56:44 mail dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=52.125.136.0, lip=96.30.197.163, TLS: Disconnected, session=<xzKddPChQFk0fYgA> Mar 28 20:56:44 mail postfix/submission/smtpd[10513]: Anonymous TLS connection established from unknown[52.125.136.0]: TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits) Mar 28 20:56:44 mail postfix/submission/smtpd[10513]: lost connection after STARTTLS from unknown[52.125.136.0] Mar 28 20:56:44 mail postfix/submission/smtpd[10513]: disconnect from unknown[52.125.136.0] ehlo=1 starttls=1 commands=2 Mar 28 20:57:09 mail dovecot: imap-login: Login: user=<[email protected]>, method=LOGIN, rip=52.125.136.162, lip=96.30.197.163, mpid=10561, TLS, session=<HOcbdvCh9rw0fYii> Mar 28 20:57:09 mail dovecot: imap([email protected]): Logged out in=11 out=416 Mar 28 20:57:09 mail postfix/submission/smtpd[10513]: connect from unknown[52.125.136.162] Mar 28 20:57:09 mail postfix/submission/smtpd[10513]: lost connection after CONNECT from unknown[52.125.136.162] Mar 28 20:57:09 mail postfix/submission/smtpd[10513]: disconnect from unknown[52.125.136.162] commands=0/0 Mar 28 20:57:09 mail postfix/submission/smtpd[10513]: connect from unknown[52.125.136.162] Mar 28 20:57:09 mail postfix/submission/smtpd[10513]: Anonymous TLS connection established from unknown[52.125.136.162]: TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits) Mar 28 20:57:09 mail postfix/submission/smtpd[10513]: disconnect from unknown[52.125.136.162] ehlo=2 starttls=1 auth=1 quit=1 commands=5 </code>
Looks like the log excerpt you posted contains just two lines about IMAP login / logout to Dovecot, and those show success. Is that session the failing one you tried from your device? Easier for you would be to keep this command running in a terminal window: Code: tail -f /var/log/mail.log | grep dovecot Then try IMAP from Outlook and monitor what happens. If nothing shows in the log, your Outlook is not connecting to your e-mail server. If connections from other e-mail applications work, the e-mail server is OK so the problem seems to be in Outlook or in network settings from the computer where you use Outlook. Or maybe you have fail2ban running and it has banned the IP-address after some number of failed attempts? There is turorial: https://www.howtoforge.com/how-to-install-an-email-server-with-ispconfig-on-debian-10/
Thank you so much for taking time and replying Taleman, Let me first of all say that although I did not change anything is working right now: Murphy's law I guess. But I am equally thankful to you and I will answer your questions in case some else looks at this tread: 1) Yes it was output just for the session I was trying to connect from. 2) Nothing showed up in mail.err only in mail.log 3) Yes connections from other email clients using IMAP worked. Also connecting from SSH using openssl also worked, that is why I was so puzzled. 4) Yes I have Fail2Ban running but I am ignoring my IP so I did not think that was the issue. At any rate I am now able to connect from my Desktop using Outlook IMAP so I am happy. Outlook Android is still failing but I will research further on my own now that Destop is working. Thanks so much again!
