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Unexpected Configuration Error `Unknown setting: ssl_server_cert_file`
by David Weingut 02 Feb '26

02 Feb '26

Hello, I upgraded from Debian 12 to 13 and thereby also from dovecot 2.3 to 2.4. Now I am facing a weird error in dovecot. The actual error is the following # doveconf -n # 2.4.1-4 (7d8c0e5759): /etc/dovecot/dovecot.conf # Pigeonhole version 2.4.1-4 (0a86619f) doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-ssl.conf line 22: ssl_server_cert_file : Unknown setting: ssl_server_cert_file The corresponding entry in my config is ssl = yes ssl_server_cert_file = /etc/letsencrypt/live/example.com/fullchain.pem ssl_server_key_file = /etc/letsencrypt/live/example.com/privkey.pem I am sorry if I missed something in the archives but I did not find any similar posts. Is there something I am missing here and what would be further required to debug this? Best, David Hello, I upgraded from Debian 12 to 13 and thereby also from dovecot 2.3 to 2.4. Now I am facing a weird error in dovecot. The actual error is the following # doveconf -n # 2.4.1-4 (7d8c0e5759): /etc/dovecot/dovecot.conf # Pigeonhole version 2.4.1-4 (0a86619f) doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-ssl.conf line 22: ssl_server_cert_file : Unknown setting: ssl_server_cert_file The corresponding entry in my config is ssl = yes ssl_server_cert_file = /etc/letsencrypt/live/example.com/fullchain.pem ssl_server_key_file = /etc/letsencrypt/live/example.com/privkey.pem I am sorry if I missed something in the archives but I did not find any similar posts. Is there something I am missing here and what would be further required to debug this? Best, David

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Compiling Dovecot 2.4 on OpenBSD
by Joel Mawhorter 02 Feb '26

02 Feb '26

I'm writing to see if anyone has had success compiling Dovecot 2.4 on OpenBSD. I can't seem to find any documentation that lists prerequisites. At the moment, the 2.4.2 source tarball from the Dovecot site does not seem to compile on my OpenBSD 7.8 system and the error message is not very helpful. I'm unsure if this is just a problem of some required package not being installed. If anyone could point me to info to help move forward, I would appreciate that. Joel

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How can these MBOX files on a Dovecot-based IMAP server be converted to PST for access in Outlook?
by Rawnie Dolgato 31 Jan '26

31 Jan '26

MBOX files stored on a Dovecot-based IMAP server cannot be accessed directly in Microsoft Outlook, because Outlook does not support the MBOX file format. Outlook works with PST files, so a conversion step is mandatory. While it is technically possible to convert MBOX files to EML and then import them into Outlook, this approach is impractical for real-world scenarios. It is time-consuming, difficult to manage, and not suitable when handling bulk mailboxes or large datasets, which is typically the case with server-level backups. For this reason, an MBOX to PST conversion tool (such as BitRecover MBOX to PST Converter) is recommended. It supports bulk MBOX data, preserves folder structure and metadata, and allows selective migration based on criteria like date, sender, or subject. The process runs 100% offline, ensuring data security, and works on Windows, macOS, and Linux, making it suitable for both single and multi-mailbox migrations.

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Meaning of auth-worker disconnected message and relation to LMTP 451 errors on Ubuntu
by Kim Haverblad 31 Jan '26

31 Jan '26

Hi dovecot list, I’m troubleshooting an LMTP delivery issue with Dovecot and would appreciate clarification on the meaning and impact of the following log message, which appears repeatedly during delivery attempts: auth-worker(2961): Debug: conn unix:auth-worker (pid=2948,uid=107): Disconnected: Connection closed (fd=-1) *Environment* * OS: Ubuntu (latest LTS, fully up to date) * Dovecot: distribution package (current version for Ubuntu) * MTA: Postfix * Delivery: LMTP to Dovecot * User database: MySQL (userdb lookup succeeds) * Mail storage: Maildir * Quotas: enabled via userdb (quota_rule) *Context* * LMTP accepts the recipient and completes userdb lookup successfully. * The mailbox path, uid, gid, and quota are correctly returned. * Postfix later receives a 451 4.3.0 Temporary internal error after the DATA phase. * The above auth-worker ... Disconnected: Connection closed (fd=-1)message appears around the same time. *Questions* 1. Is this Disconnected: Connection closed (fd=-1) message expected/normal behavior for auth-worker processes once a lookup is complete? 2. Under what circumstances would this indicate a real problem versus a harmless connection teardown? 3. Could this message itself contribute to, or explain, LMTP 451 4.3.0 Temporary internal error responses? 4. Are there specific auth-worker, LMTP, or debug settings recommended to determine whether this disconnect is abnormal? So far, authentication and userdb lookups appear clean, and there are no explicit permission or quota errors logged, which makes it unclear whether this message is relevant to the delivery failure or simply informational. Any clarification on how to interpret this log entry — and how to confirm whether it is benign or problematic — would be greatly appreciated. Kind Regards, Kim Hi dovecot list, I'm troubleshooting an LMTP delivery issue with Dovecot and would appreciate clarification on the meaning and impact of the following log message, which appears repeatedly during delivery attempts: auth-worker(2961): Debug: conn unix:auth-worker (pid=2948,uid=107): Disconnected: Connection closed (fd=-1) Environment o OS: Ubuntu (latest LTS, fully up to date) o Dovecot: distribution package (current version for Ubuntu) o MTA: Postfix o Delivery: LMTP to Dovecot o User database: MySQL (userdb lookup succeeds) o Mail storage: Maildir o Quotas: enabled via userdb (quota_rule) Context o LMTP accepts the recipient and completes userdb lookup successfully. o The mailbox path, uid, gid, and quota are correctly returned. o Postfix later receives a 451 4.3.0 Temporary internal error after the DATA phase. o The above auth-worker ... Disconnected: Connection closed (fd=-1) message appears around the same time. Questions 1. Is this Disconnected: Connection closed (fd=-1) message expected/normal behavior for auth-worker processes once a lookup is complete? 2. Under what circumstances would this indicate a real problem versus a harmless connection teardown? 3. Could this message itself contribute to, or explain, LMTP 451 4.3.0 Temporary internal error responses? 4. Are there specific auth-worker, LMTP, or debug settings recommended to determine whether this disconnect is abnormal? So far, authentication and userdb lookups appear clean, and there are no explicit permission or quota errors logged, which makes it unclear whether this message is relevant to the delivery failure or simply informational. Any clarification on how to interpret this log entry -- and how to confirm whether it is benign or problematic -- would be greatly appreciated. Kind Regards, Kim

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sieve auto-creation/subscription - Thunderbird cannot re-arrange folders
by listy 31 Jan '26

31 Jan '26

Hi guys. In Thunderbird auto-subscribed folders - in my case a path with sub-folders - cannot be moved around, meaning top-bottom order. Parent folders Thunderbird shows in cursive and sub-folders (targets for sieve fules) are shown "normal" It seems impossible to re-arrange top/parent folders - but every other folder, top or not, which is not auto created & auto subscribed, Thunderbird can move around as expected. Anybody seen, anybody knows this and knows a way to "fix" it? many thanks, L.

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How can these MBOX files on a Dovecot-based IMAP server be accessed in Outlook?
by Rawnie Dolgato 31 Jan '26

31 Jan '26

MBOX files stored on a Dovecot-based IMAP server cannot be accessed directly in Microsoft Outlook, because Outlook does not support the MBOX file format. Outlook works with PST files, so a conversion step is mandatory. While it is technically possible to convert MBOX files to EML and then import them into Outlook, this approach is impractical for real-world scenarios. It is time-consuming, difficult to manage, and not suitable when handling bulk mailboxes or large datasets, which is typically the case with server-level backups. For this reason, an MBOX to PST conversion tool (such as BitRecover MBOX to PST Converter) is recommended. It supports bulk MBOX data, preserves folder structure and metadata, and allows selective migration based on criteria like date, sender, or subject. The process runs 100% offline, ensuring data security, and works on Windows, macOS, and Linux, making it suitable for both single and multi-mailbox migrations.

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Subscriptions file broken in 2.4.x against 2.3.21 (V2)
by DaLiV 31 Jan '26

31 Jan '26

Hello! /eror at update from 2.3.21 to 2.4.2 / Maildir+ currently is broken. posix - so main hierarchy separator is "/" for file "subscriptions" in versions 2.4 lost possibility to recognize v2 format also as writes v1 instead with header V2 ... so all users will lost their subscriptions and must re-subscribe depsite in folder persist file in format V2 (tab separated) ... on subscribe that appends subscriptions delimeted with "/" namespace Public { type = public prefix = Public/ mail_driver = maildir mail_path = /var/mail/Public/%{auth_user|domain}/ mail_index_private_path = pvt.idx/Public mailbox_list_layout=fs separator = / subscriptions = no list = children } seems not taking in account separators and using "." instead of "/" slighlz debugged - in subsfile_set_subscribed - that gets on subscription for processing : "name"="Public/TEST" but "separator" = "." therefore splits not and decides that is version "0" ... so - somewhere deeper or possible need additional configuration Hello! eror at update from 2.3.21 to 2.4.2 Maildir+ currently is broken. posix - so main hierarchy separator is "/" for file "subscriptions" in versions 2.4 lost possibility to recognize v2 format also as writes v1 instead with header V2 ... so all users will lost their subscriptions and must re-subscribe depsite in folder persist file in format V2 (tab separated) ... on subscribe that appends subscriptions delimeted with "/" namespace Public { type = public prefix = Public/ mail_driver = maildir mail_path = /var/mail/Public/%{auth_user|domain}/ mail_index_private_path = pvt.idx/Public mailbox_list_layout=fs separator = / subscriptions = no list = children } seems not taking in account separators and using "." instead of "/" slighlz debugged - in subsfile_set_subscribed - that gets on subscription for processing : "name"="Public/TEST" but "separator" = "." therefore splits not and decides that is version "0" ... so - somewhere deeper or possible need additional configuration

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New Member
by Jochen Becker 30 Jan '26

30 Jan '26

Hi all My name is Jochen and I have joined the list in order to get some first hand advice on my journey of migrating my SOHO mail server from 2.3 to 2.4. I set up my first server back in 2005 or so. OpenSuse and Cyrus IMAP. That went fine until all of a sudden, some 8 or 10 years ago, Suse no longer supported Cyrus directly. So I switched over to Dovecot and did not regret it. My current production server (OpenSuse Leap 16, Dovecot 2.4.2) is running fine after a recent migration. But the HW is ageing and disk usage is getting close to 80%. So I got new and larger HW. I run OpenSuse Leap 16.0 and Dovecot 2.4.2 on it. As I ran into unsurmountable problems there (could not move mail_path away from /var/mail), I decided to set up a test system under Ubuntu server 25.10. There I have got Dovecot running much better, but still, I ran into problems I could not solve for quite some time now. So here I am. I will start with questions about Dovecot on Ubuntu - my test system - because there I hope my mistakes are not as bad. Aki, thanks for taking me on board. Kind regards Jochen Mainz, Germany

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Re: Panic: file imap-sieve-storage.c: line 216 (imap_sieve_add_mailbox_event): assertion failed: (ismt->src_box == NULL || ismt->src_box == src_box)
by Jeffrey Böhm 29 Jan '26

29 Jan '26

Hi, I’m seeing the same issue after upgrading to Dovecot 2.4.2. I reproduced it with both the Alpine Linux build and the official Dovecot Docker image referenced at [1]. In my case, the crash correlates strongly with iOS devices auto-deleting older messages from the Trash folder. As Christian described, it starts after a larger number of IMAP MOVE operations. Key finding: when I disable the imap_sieve extensions, the crashes stop. Personal Sieve rules continue to work as expected, so the problem appears to be specific to imap_sieve (or its interaction with frequent MOVE operations). > sieve_plugins { > sieve_imapsieve = no > } > > protocol imap { > mail_plugins { > imap_sieve = no > imap_filter_sieve = no > } > } My configuration with the enabled imap_sieve extension is located at [2]. Kind regards Jeff [1]: https://github.com/dovecot/docker [2]: https://github.com/jeboehm/docker-mailserver/blob/7433443ebd4af1c422cb4030c…

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Migration to 2.4: Howto get the quota dict writing into a second DB
by volker.jaenisch＠inqbus.de 29 Jan '26

29 Jan '26

Dear Dovecot wizards! I have a question concerning the migration from 2.3.4 to 2.4.1. On 2.3.4 I had the following config dict { sql_store_user_quota = pgsql:/etc/dovecot/dovecot-sql-store-user_quota.conf } With /etc/dovecot/dovecot-sql-store-user_quota.conf: connect = host=127.0.0.1 port=5433 dbname=dddd user=uuuu password=pppp: map { pattern = priv/quota/storage table = fill_user username_field = username value_field = bytes } map { pattern = priv/quota/messages table = messages_user username_field = username value_field = messages } On 2.4.1 I tried dict_map priv/quota/storage { sql_table = emailaddress_fill username_field = emailaddress dict_map_value_field quota_bytes { type = uint } } dict fill { sql_driver = pgsql pgsql pg_mc2 { parameters { dbname = dddd host = hhhh password = ppppp user = uuuuu } } } But it is doing nothing. Am sure I am missing something here (I guess howto connect these config snippets). Any help appreciated. Cheers, Volker -- =========================================================== inqbus Scientific Computing GmbH Dr. Volker Jaenisch Hungerbichlweg 3 +49 (8860) 9222 7 92 86977 Burggen https://inqbus.de ===========================================================

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