1 Topic by diana.lohmus (edited by diana.lohmus 2021-02-06 18:49:22)

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Topic: smtp port :587 not working in outlook mobile apps

==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.3.2 MARIADB edition
- Deployed with iRedMail Easy or the downloadable installer? iRedMail Easy
- Linux/BSD distribution name and version: CentOS Linux release 7.9.2009 (Core)
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): Mysql
- Web server (Apache or Nginx): nginx/1.16.1
- Manage mail accounts with iRedAdmin-Pro? Yes
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====
I can receive all e-mails but cant send. There is no specific error message - only e-mail goes to draft.
In maillog I can see: postfix/submission/smtpd[13726]: timeout after UNKNOWN

I tested IMAP account in different android and apple devices.  Cant sent any e-mail. All works in android phone outlook app, when I use exchange settings. But IMAP account works well only in computer app - Outlook 2016 and outlook 2019.

I just discovered that for some reason mobile phone IP is being banned. password and username are correct, I double checked.

----

Spider Email Archiver: On-Premises, lightweight email archiving software developed by iRedMail team. Supports Amazon S3 compatible storage and custom branding.

2 Reply by ZhangHuangbin

  • ZhangHuangbin
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Re: smtp port :587 not working in outlook mobile apps

Is the IP banned by Fail2ban while the issue happening?

3 Reply by diana.lohmus (edited by diana.lohmus 2021-02-09 20:34:50)

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Re: smtp port :587 not working in outlook mobile apps

ZhangHuangbin wrote:

Is the IP banned by Fail2ban while the issue happening?

No, not immediately. IP will banned after 5 attempts send email out.

Maillog:
Feb  9 14:20:42 mail postfix/submission/smtpd[29834]: connect from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:20:42 mail postfix/submission/smtpd[29835]: connect from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:20:42 mail postfix/submission/smtpd[29835]: lost connection after UNKNOWN from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:20:42 mail postfix/submission/smtpd[29835]: disconnect from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:20:42 mail postfix/submission/smtpd[29835]: connect from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:23:54 mail postfix/anvil[8953]: statistics: max connection rate 8/60s for (submission:46.131.33.220) at Feb  9 14:20:42
Feb  9 14:23:54 mail postfix/anvil[8953]: statistics: max connection count 5 for (submission:46.131.33.220) at Feb  9 14:20:42
Feb  9 14:25:08 mail postfix/submission/smtpd[29854]: connect from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:25:08 mail postfix/submission/smtpd[29854]: lost connection after UNKNOWN from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:25:08 mail postfix/submission/smtpd[29854]: disconnect from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:25:42 mail postfix/submission/smtpd[25277]: timeout after UNKNOWN from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:25:42 mail postfix/submission/smtpd[25277]: disconnect from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:25:42 mail postfix/submission/smtpd[29832]: timeout after UNKNOWN from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:25:42 mail postfix/submission/smtpd[29832]: disconnect from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:25:42 mail postfix/submission/smtpd[29833]: timeout after UNKNOWN from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:25:42 mail postfix/submission/smtpd[29833]: disconnect from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:25:42 mail postfix/submission/smtpd[29834]: timeout after UNKNOWN from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:25:42 mail postfix/submission/smtpd[29834]: disconnect from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:25:42 mail postfix/submission/smtpd[29835]: timeout after UNKNOWN from 220-33-131-46.dyn.estpak.ee[46.131.33.220]
Feb  9 14:25:42 mail postfix/submission/smtpd[29835]: disconnect from 220-33-131-46.dyn.estpak.ee[46.131.33.220]

And Fail2ban log:
2021-0 2-09T14:19:29.763766mail.saare.ee postfix/submission/smtpd[24840]: lost connection after UNKNOWN from 220-33-131-46.dyn.estpak.ee[46.131.33.220]

2021-0 2-09T14:20:42.414592mail.saare.ee postfix/submission/smtpd[29834]: lost connection after UNKNOWN from 220-33-131-46.dyn.estpak.ee[46.131.33.220]

2021-0 2-09T14:20:42.507655mail.saare.ee postfix/submission/smtpd[29834]: lost connection after UNKNOWN from 220-33-131-46.dyn.estpak.ee[46.131.33.220]

2021-0 2-09T14:20:42.699971mail.saare.ee postfix/submission/smtpd[29835]: lost connection after UNKNOWN from 220-33-131-46.dyn.estpak.ee[46.131.33.220]

2021-0 2-09T14:25:08.920946mail.saare.ee postfix/submission/smtpd[29854]: lost connection after UNKNOWN from 220-33-131-46.dyn.estpak.ee[46.131.33.220]

4 Reply by R24-AdminSports

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Re: smtp port :587 not working in outlook mobile apps

After an exhaustive day trying to troubleshoot this, here is our contribution to the problem. TLDR, still exists.


iRedMail: 1.3.2

Product name: iRedAdmin-Pro-SQL
Latest version: 4.7 (You are running version 4.7)

iOS: 14.5
Outlook for iOS version: 4.2109.0  (updated 2 days ago)

Outlook iOS configured for IMAP/SMTP
We tried setting ports (587 and 465), both had same issue

SYMPTOM
When sending an email, mail sits in the outbox and never goes out.
For example, start new message, enter the recipient and the send button (upper-right) turns white after entering a valid email address.
Enter subject/body, next you hit the SEND button. This is where it stops, it remains stuck with send button visible.
When hitting SEND, we can see traffic on 465 or 587 using TCP dump, but negotiation never completes.
The message remains stuck in the outbox.

On the server, we see a connection timeout along with a UTF8 error.
-- from /var/log/mail.log
postfix/submission/smtpd[13236]: timeout after UNKNOWN from unknown
-- utf error (visible from tcpdump)
5.5.2 Error: bad UTF-8 syntax

Things we've tried
- Tested with another postfix server (no issue)
- Disabled the Wifi Private Address feature (new in iOS)
- Disabled fail2ban, flushed iptables and set our IP to be ignored in /etc/fail2ban/jail.local
- Rebooted server
- Wifi disabled, same results on cellular data.
- Logged out of iCloud/deleted app/logged into iCloud and reinstalled Outlook.
- Tested on iOS   "14.5 (18E5140k)"  and "14.5 (18E5164h)"
- using tcpdump, we noticed this during smtp connection on port 587
                5.5.2 Error: bad UTF-8 syntax
- Tried a UTF8 change in main.cf and amavis (see below)

    https://forum.iredmail.org/topic15252-p … pport.html
## From this post, we tried
-- added to main.cf
smtputf8_enable = yes
smtputf8_autodetect_classes = sendmail, verify
-- Commented both occurrences in /etc/amavis/conf.d/50-user
# smtpd_discard_ehlo_keywords => ['8BITMIME'],

5 Reply by jung

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Re: smtp port :587 not working in outlook mobile apps

Hi R24-AdminSports and diana.lohmus,

How sad... It happened to me last month until now. Outlook can't send email with attachment larger than 1mb and stayed in outbox forever with the same error as yours.

I've disabled, fail2ban,spamassassin,ufw,iptables but did not fix the issue. I'm using lets encrypt cert. tried using outlook 2010,2013,2016 and even outlook365 and thunderbird but sending over smtp port 587-tls is not working....

Tried to allow any any outgoing port in our cisco firewall but to no avail.

Hope somebody shared their technical knowledge.

In Fairness to Zhang, he is doing his very best to help us resolved this issue.

Thanks.
JunG

6 Reply by ZhangHuangbin

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Re: smtp port :587 not working in outlook mobile apps

I did a quick test with the latest Outlook mobile app and latest iOS, no issue at all.
Not sure why it doesn't work on your server and mobile app. sad

7 Reply by R24-AdminSports

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Re: smtp port :587 not working in outlook mobile apps

After almost a week - going back and forth with a Microsoft Support tech, they have come out and explicit told me that they are aware of the issue that pertains directly to their app:

"... I've checked on our resources, and found that this is currently a known issue. We're sorry for the inconvenience that this has brought you.

Our engineers are working to have this issue resolved, however, there's no exact date as to when the fix will be available. Always update you Outlook app, though, as the fix will be in a form of an app update..."

- Luis

I received this response at 3:33pm today. Just thought I'd share with the community as we've all be scratching our heads over this one and have had a few sleepless nights.

8 Reply by ZhangHuangbin

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Re: smtp port :587 not working in outlook mobile apps

Thanks for sharing. smile

9 Reply by oborseth (edited by oborseth 2021-08-27 08:57:41)

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Re: smtp port :587 not working in outlook mobile apps

Not sure if this will work in your case but for us we resolved the issue by using implicit TLS via port 465 (must configure port 456 service for implicit TLS). The Outlook bug appears to be limited to its implementation of STARTTLS (explicit TLS), at least for us.