February 2026 - dovecot

[Dovecot] migration from IMAP/POP3 courier server to a remote dovecot server
by nik600 06 Apr '26

06 Apr '26

Dear all i'm planning a transparent migration from a courier server that provides both IMAP and POP3 access to users to a remote dovecot server with both IMAP and POP3 access. I have to migrate about 2500 users for 250 GB of space. I'm using dovecot 2.2.5.4 on debian6 squeeze. To make a transparent migration i have to maintain old IMAP UIDs and POP3 UIDs, so i've read http://wiki2.dovecot.org/Migration and http://wiki2.dovecot.org/Migration/Courier and http://wiki2.dovecot.org/Migration/Dsync And decided that probably the best tool to use is Dsync, as the courier-dovecot-migrate.pl<http://www.dovecot.org/tools/courier-dovecot-migrate.pl> script works only locally. I've tested the dsync following instructions reported above but after the migration of one test-account the client re-download messages. If i want to keep both IMAP UIDs and POP3 UIDs i have to sync both imapc and pop3c with two commands? doveadm -o imapc_user=foo -o pop3c_user=foo -o imapc_password=bar -o pop3c_password=bar backup -R -u user@domain imapc: doveadm -o imapc_user=foo -o pop3c_user=foo -o imapc_password=bar -o pop3c_password=bar backup -R -u user@domain pop3c: Or imapc is enough? Do you have any suggestion? Thanks -- /*************/ nik600 http://www.kumbe.it

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Error: ldap: auth_passdb_post settings
by Ruud Baart 21 Mar '26

21 Mar '26

Dovecot 2.4.1 works fine on my Debian Trixie server. I use LDAP as backend for the users. I don't have problems. Authentication works fine. However logging show every time the following line: auth-worker(<user name@domain,::1)<109040><3v5ddOlJvrgAAAAAAAAAAAAAAAAAAAAB>: request [7]: Error: ldap: auth_passdb_post settings: Failed to parse configuration: Failed to expand passdb_fields/password setting variables: ldap: No such attribute 'userpassword' The LDAP authentication works correct. So I don't understand this message. My correct working LDAP configuration in auth-ldap.conf.ext: passdb ldap { passdb_use_worker = yes passdb_ldap_filter = (&(objectClass=PromptMailUser)(accountStatus=TRUE)(mailDeliveryaddress=%{user})) ldap_bind = yes fields { user = %{ldap:mailDeliveryaddress} password = %{ldap:userPassword} } } userdb ldap { userdb_use_worker = yes userdb_ldap_filter = (&(objectClass=PromptMailUser)(accountStatus=TRUE)(mailDeliveryaddress=%{user})) fields { home = %{ldap:mailBase} mail = %{ldap:mailMessageStore} mail_path = %{ldap:mailMessageStore} quota_storage_size = %{ldap:dovecotQuota} } }

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Panic in logs
by Kamil Jońca 21 Mar '26

21 Mar '26

Recently I found in my lda logs: 2025-12-30T07:55:14.717927+01:00 alfa dovecot: lda(kjonca): Error: Raw backtrace: #1 [unw_get_proc_name() failed: -10] -> #2 i_syslog_fatal_handler[0x7f99a2351430] -> #3 i_panic[0x7f99a226d453] -> #4 [unw_get_proc_name() failed: -10] -> #5 [unw_get_proc_name() failed: -10] -> #6 [unw_get_proc_name() failed: -10] -> #7 buffer_append[0x7f99a2345270] -> #8 dregex_code_match_groups[0x7f99a233f1a0] -> #9 [unw_get_proc_name() failed: -10] -> #10 [unw_get_proc_name() failed: -10] -> #11 sieve_match_value[0x7f99a117f770] -> #12 sieve_match[0x7f99a117fa30] -> #13 [unw_get_proc_name() failed: -10] -> #14 sieve_interpreter_continue[0x7f99a117e100] -> #15 sieve_multiscript_run[0x7f99a1190330] -> #16 [unw_get_proc_name() failed: -10] -> #17 mail_deliver[0x7f99a27e54a0] -> #18 main[0x55e371c555e0] -> #19 __libc_start_call_main[0x7f99a1e29f00] -> #20 __libc_start_main_alias_2[0x7f99a1e29fa0] -> #21 _start[0x55e371c566a0] And sadly it seems, that mail is missing (it was passed to pipe program to further processing) KJ -- http://wolnelektury.pl/wesprzyj/teraz/ When you go out to buy, don't show your silver.

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shared mailbox error
by Marc 19 Mar '26

19 Mar '26

I am getting this error. This file does not exist. Error: t_readlink(/xxxxxx/dbox-alt-root) failed: readlink() failed: Permission denied

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How to declare port 143
by Steve Litt 10 Mar '26

10 Mar '26

Hi all, I have Dovecot 2.4.2 working (plain text only) on my Qemu virtual machine, with Claws-Mail able to work with all its files. However, I want to declare the Dovecot server as running on Port 143, and when I do, I dovecot -F throws the error message shown later in this message. If I comment out the explicit port declaration, it works fine, and I want to know why. To the best of my knowledge, my declaration of port 143 exactly matches your 2.4.2 documentation: The following is my attempt to tell Dovecot to serve *explicitly* at port 143: =============================================== # My Dovecot server will operate on Localhost listen = 127.0.0.1 service imap { inet_listener imap-login { port = 143 } # inet_listener imaps { # port = 993 # ssl = yes # } } =============================================== The following is the result: =============================================== [root@dovecotvoid ~]# dovecot -F doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf: duplicate listener: 143:127.0.0.1 [root@dovecotvoid ~]# =============================================== If I comment out the port = 143, it works. Why is it griping about a duplicate listener? At the bottom of this email is the entire dovecot.conf and the result of dovecot -n, and there are no sub-configuration files in conf.d : =============================================== # Start new configs with the latest Dovecot version numbers here: dovecot_config_version = 2.4.2 # Must be current version dovecot_storage_version = 2.4.2 # Must be current version or earlier # 2.3 is minimum # I only want imap protocols { imap = yes lmtp = no pop3 = no } # My Dovecot server will operate on Localhost listen = 127.0.0.1 service imap { inet_listener imap-login { port = 143 } # inet_listener imaps { # port = 993 # ssl = yes # } } # mail_home is only for virtual users # A virtual user is a user with no system account # I have no virtual users, so I've commented out mail_home. #mail_home = /srv/mail/%{user} # mail_driver is the storage format mail_driver = maildir # mail_path is location of top of storage data # WARNING: For troubleshooting be prepared to switch # to literal location of ~ mail_path = ~/mail/Maildir # In my case # mail_home is the home directory of the user identified as ~ # WARNING: system users have no ~ without it. mail_home = /home/slitt # You need a log you can locate # There might not be a log_path=/var/log/dovecot.log #mail_uid = slitt #mail_gid = slitt mail_uid = vmail mail_gid = vmail # By default first_valid_uid is 500. #If your vmail user's UID is smaller, # you need to modify this: #first_valid_uid = uid-number-of-vmail-user namespace inbox { inbox = yes separator = / } # Authenticate as system users: passdb pam { driver = pam #driver = passwd } userdb passwd { driver = passwd } #ssl_server_cert_file = /etc/dovecot/ssl-cert.pem #ssl_server_key_file = /etc/dovecot/ssl-key.pem =============================================== The following is the output of dovecot -n: =============================================== # 2.4.2 (0962ed2104): /etc/dovecot/dovecot.conf # OS: Linux 6.12.71_1 x86_64 # Hostname: dovecotvoid dovecot_config_version = 2.4.2 dovecot_storage_version = 2.4.2 listen = 127.0.0.1 log_path = /var/log/dovecot.log mail_driver = maildir mail_gid = vmail mail_home = /home/slitt mail_path = ~/mail/Maildir mail_uid = vmail protocols { imap = yes lmtp = no pop3 = no } service imap { inet_listener imap-login { port = 143 } } namespace inbox { inbox = yes separator = / } passdb pam { driver = pam } userdb passwd { driver = passwd } ===============================================

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Dovecot 2.4 doveadm_worker_count corrupts tab-formatted output
by Philip Iezzi 08 Mar '26

08 Mar '26

Hi there On a Dovecot 2.4.2 (Debian Bookworm) server with over 1300 users, I am using the following config to retrieve quota usage information with doveadm: --------------------------------------- quota "User quota" { } mail_plugins = quota acl mail_log notify userdb sql { iterate_query = SELECT username AS user, CONCAT(quota, 'M') AS quota_storage_size FROM mailaccounts WHERE active = 1 query = \ SELECT '/var/vmail/%{user | domain}/%{user | username}' AS home, 'vmail' AS uid, 'vmail' AS gid, CONCAT(quota, 'M') AS quota_storage_size \ FROM mailaccounts \ WHERE username = '%{user}' AND (active = 1 OR transport_suspended = 0) } --------------------------------------- Initially, I had to run `doveadm quota recalc -A` to recalc quotas and populate the `count` quota driver which is enabled by default for "User quota". But still, it took roughly 20ms per single user or 15-20s for all users: $ time doveadm -f tab quota get -u demo(a)example.com real 0m0.020s $ time doveadm -f tab quota get -A real 0m16.800s Now, to greatly speed this up, I have introduced parallel processing: doveadm_worker_count = 4 Like this, `doveadm -f tab quota get -A` runs approx 10x faster, done in 1.5 - 2.5s But there is one major drawback which I assume to be a bug: # sane output without `doveadm_worker_count = 4` => always 6 fields demo(a)example.com User quota STORAGE 29 204800 0 demo(a)example.com User quota MESSAGE 1 - 0 # broken output with `doveadm_worker_count = 4` => sometimes 7 fields demo(a)example.com User quota STORAGE 29 2048 00 0 demo(a)example.com User quota MESSAGE 1 - 0 Somehow, the tab formatter does not play nicely together with parallel processing. On some output, the value gets split apart by an extra tab, e.g. '2024<TAB>00' in above example. Can you explain this corrupted data? Some kind of "output interleaving" seems to happen when running parallel workers. If I switch to json output (`doveadm -f json quota get -A`), this does not seem to happen and I always get valid JSON output, even with `doveadm_worker_count = 4`. Cheers, Philip

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Dovecot marking outgonig emails as unread
by stef204 03 Mar '26

03 Mar '26

Starting a few days ago, I have one email account where ALL outgoing emails are automatically marked as UNREAD. The message is sent, then copied to the "Sent" folder, and has status "unread". Then, a couple of minutes later, something happens where this message gets marked as UNREAD, without ANY interaction of client side. This occurs not matter the email client used, I have tried it with multiple email clients, both local and via web interface, the behavior does not change. This is via Dovevot on Cpanel. if I look at the [1]changelog, it is difficult to identify which changes could have triggered this as there seem to be changes impacting Dovecot almost with every update. I do not control the server myself, this is on a shared hosting plan; tech support has been willing to troubleshoot but is unable to locate the problem. This problem does NOT occur on other email accounts on the same domain, so it looks to me like some corruption or problem syncing flags perhaps? I am at a loss at the moment to fix this behavior. Any suggestions or ideas welcome. Thanks. References Visible links 1. https://docs.cpanel.net/changelogs/132-change-log/

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[Pigeonhole] extracttext on "message/rfc822" attachment ignores included headers
by quentinduchemin＠tuta.io 03 Mar '26

03 Mar '26

Hi everyone! I'm not sure this is a design decision, a bug, something not implemented or malformed input on my side. My use case is the following: users that forward their mails outside the domain I manage have the option to report spam as attachment so the spam classifier can learn anyway. I prefer attachment over forward because MUAs have their own way to do it and it's difficult to reliably reconstruct some headers/email structure that can be important for the spam classifier. Each input message is processed through a Sieve extensions of RFC 5703 to extract the attachment. I ask user to produce a file with .eml extension through any export-like feature of their MUA. Below is an example EML file produced by Tuta (Thunderbird does a similar thing with a different encoding for the body). I'll use a bunch of = characters as a separator in the rest of this. =============================================== [...bunch of header...] X-MS-Exchange-CrossTenant-rms-persistedconsumerorg: 00000000-0000-0000-0000-0000000000 00 X-MS-Exchange-Transport-CrossTenantHeadersStamped: TYSPR04MB7035 Content-Type: multipart/related; boundary="------------79Bu5A16qPEYcVIZL@tutanota" --------------79Bu5A16qPEYcVIZL@tutanota Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: base64 DQo8ZGl2IHN0eWxlPSJmb250LWZhbWlseTogQXB0b3MsIEFwdG9zX0VtYmVkZGVkRm9udCwgQXB0b3 NfTVNGb250U2VydmljZSwgQ2FsaWJyaSwgSGVsdmV0aWNhLCBzYW5zLXNlcmlmOyBmb250LXNpemU6 [...base64 encoding of the body...] =============================================== While attached and sent, the received messaged looks like this: =============================================== [...headers of the actual email...] X-Infomaniak-Routing: alpha This is a multi-part message in MIME format. --------------5jyKrhQ08xXUif7LHhgg648N Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit --------------5jyKrhQ08xXUif7LHhgg648N Content-Type: message/rfc822; name="a.eml" Content-Disposition: attachment; filename="a.eml" Content-Transfer-Encoding: 7bit [...headers of the spam....] Subject: Re: //Re: AI + Ranking /// Thread-Topic: //Re: AI + Ranking /// [....] Content-Type: multipart/related; boundary="------------79Bu5A16qPEYcVIZL@tutanota" --------------79Bu5A16qPEYcVIZL@tutanota Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: base64 DQo8ZGl2IHN0eWxlPSJmb250LWZhbWlseTogQXB0b3MsIEFwdG9zX0VtYmVkZGVkRm9udCwgQXB0b3 NfTVNGb250U2VydmljZSwgQ2FsaWJyaSwgSGVsdmV0aWNhLCBzYW5zLXNlcmlmOyBmb250LXNpemU6 [...base64 encoding of the spam....] --------------79Bu5A16qPEYcVIZL@tutanota-- --------------5jyKrhQ08xXUif7LHhgg648N-- =============================================== I face two issues: 1. Only the base64 decoded string can be retrived through foreverypart/extracttext; 2. It has a lot of newlines. - 2. is not a big deal. The original spam has a lot of HTML junk, and each line with HTML without an inner text node is stripped, but the newline is kept. I don't know if this is intended. - 1. is more of a big deal. To try to confirm that, I made an over-simplified version of the Sieve script (I skip configuration but plugins are loaded etc, please ask if useful). =============================================== [...require...] foreverypart { extracttext "eml"; debug_log "PART ============================== ${eml}"; } =============================================== mail_debug is activated. In the logs, I can read: =============================================== Info: sieve: DEBUG: PART ============================== Info: sieve: DEBUG: PART ============================== Info: sieve: DEBUG: PART ============================== Info: sieve: DEBUG: PART ============================== Info: sieve: DEBUG: PART ============================== Info: sieve: Info: sieve: Info: sieve: Info: sieve: Info: sieve: Info: sieve: Info: sieve: Hello, Info: sieve: Info: sieve: Hope you're doing well. Info: sieve: Info: sieve: Info: sieve: Info: sieve: Info: sieve: Would you like attract more traffic with our AEO + GEO + SEO services. AI-driven search is here—don’t miss out. =============================================== So multiple parts are analyzed but only the last gives something. The RFC says that "If the transfer encoding or character set is unrecognized by the implementation or recognized but invalid, an empty string will result.". But it's over my knowledge. I activated trace for Sieve with "matching" level, and the file looks like (this is another test but was the same result): =============================================== Sieve trace log for message delivery: Username: REDACTED Session ID: ozNMOEPNl2nlAAAAO14Lzw Sender: REDACTED Final recipient: REDACTED Default mailbox: INBOX ## Started executing script 'move-spam' 33: foreverypart loop begin 33: loop ends at line 36 35: extracttext command 36: assign 'eml' [0] = "" 36: debug_log "PART ============================== " 36: foreverypart loop end 36: switched to next message part 36: looping back to line 35 35: extracttext command 36: assign 'eml' [0] = "" 36: debug_log "PART ============================== " 36: foreverypart loop end 36: switched to next message part 36: looping back to line 35 35: extracttext command 36: assign 'eml' [0] = "" 36: debug_log "PART ============================== " 36: foreverypart loop end 36: switched to next message part 36: looping back to line 35 35: extracttext command 36: assign 'eml' [0] = "" 36: debug_log "PART ============================== " 36: foreverypart loop end 36: switched to next message part 36: looping back to line 35 35: extracttext command 36: assign 'eml' [0] = "Hi, Just checking in to see if you had a chance to review my earlier message. [...body spam....] 36: debug_log "PART ============================== ????????????Hi, ?? ??Just checking in t..." 36: foreverypart loop end 36: no more message parts 36: exiting loops at line 36 ## Finished executing script 'move-spam' =============================================== Hypothesis: A. Could it be because the mail headers are indistinguishable from the part headers? B. Or is it related to Pigeonhole not implementing yet the enclose extension, which do this the other way? I hope this message is not too hard to read with all the code/logs. Please tell me if there is a better way of doing it. And thanks in advance for any help, because I don't really know what to do and trying to take a (superficial) look at the Pigeonhole code didn't helped.

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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 Christian Kivalo 28 Feb '26

28 Feb '26

Reposting my reply from a few days ago to a thread with the same panic message. I found this in my logs when some mails that got deleted on the phone were still visible in roundcube. I currently have three users that trigger the panic. One user with an iPad accounts for nearly all of the panics. The problem shows when the account is accessed from android (thunderbird) or ipad. The same accounts show no problems when beeing used with roundcube or thunderbird on windows. I enabled core dumps on 2026-01-14 and have ~8500 core dumps of the imap binary until now. What causes this error and how can I fix it? In the logs all I see is the users login, then the panic. # doveconf -n # 2.4.2-2+debian13 (0962ed2104): /etc/dovecot/dovecot.conf # Pigeonhole version 2.4.2-2+debian13 (767418c3) # OS: Linux 6.12.0-custom.kvm x86_64 Debian 13.3 ext4 2026-01-13T21:44:32.317609+01:00 uschi dovecot: imap-login: Logged in: user=<user(a)example.com>, method=PLAIN, rip=<IP1>, lip=<IP2>, mpid=4194077, TLS, session=<cpkID0tId7dUc9rl> 2026-01-13T21:44:38.455379+01:00 uschi dovecot: imap(user(a)example.com)<4194077><cpkID0tId7dUc9rl>: Panic: file imap-sieve-storage.c: line 216 (imap_sieve_add_mailbox_event): assertion failed: (ismt->src_box == NULL || ismt->src_box == src_box) 2026-01-13T21:44:38.458755+01:00 uschi dovecot: imap(user(a)example.com)<4194077><cpkID0tId7dUc9rl>: Error: Raw backtrace: #1 [unw_get_proc_name() failed: -10] -> #2 [unw_get_proc_name() failed: -10] -> #3 i_panic[0x7f6b6c46c2f6] -> #4 [unw_get_proc_name() failed: -10] -> #5 [unw_get_proc_name() failed: -10] -> #6 [unw_get_proc_name() failed: -10] -> #7 mailbox_save_alloc[0x7f6b6ca103c0] -> #8 [unw_get_proc_name() failed: -10] -> #9 command_exec[0x55654e677400] -> #10 [unw_get_proc_name() failed: -10] -> #11 [unw_get_proc_name() failed: -10] -> #12 [unw_get_proc_name() failed: -10] -> #13 client_handle_input[0x55654e67ddc0] -> #14 client_continue_pending_input[0x55654e67e0b0] -> #15 io_loop_call_io[0x7f6b6c565490] -> #16 io_loop_handler_run_internal[0x7f6b6c567230] -> #17 io_loop_handler_run[0x7f6b6c5673c0] -> #18 io_loop_run[0x7f6b6c5675a0] -> #19 master_service_run[0x7f6b6c4b27f0] -> #20 main[0x55654e6688a0] -> #21 [unw_get_proc_name() failed: -10] -> #22 __libc_start_main[0x7f6b6c234ce0] -> #23 _start[0x55654e668eb0] 2026-01-13T21:44:38.459536+01:00 uschi dovecot: imap(user(a)example.com)<4194077><cpkID0tId7dUc9rl>: Fatal: master: service(imap): child 4194077 killed with signal 6 (core dumps disabled - https://dovecot.org/bugreport.html#coredumps) # coredumpctl dump PID: 1071230 (imap) UID: 5000 (vmail) GID: 5000 (vmail) Signal: 6 (ABRT) Timestamp: Fri 2026-01-16 19:17:15 CET (2s ago) Command Line: $'dovecot/imap [user(a)example.com <IP redacted> UID MOVE]' Executable: /usr/lib/dovecot/imap Control Group: /system.slice/dovecot.service Unit: dovecot.service Slice: system.slice Boot ID: 3668d179bda340229a780d5d43e426c3 Machine ID: 05698baa30ae984c9bd014566e16da18 Hostname: uschi Storage: /var/lib/systemd/coredump/core.imap.5000.3668d179bda340229a780d5d43e426c3.1071230.1768587435000000.zst (present) Size on Disk: 1.1M Message: Process 1071230 (imap) of user 5000 dumped core. Module libgcc_s.so.1 from deb gcc-14-14.2.0-19.amd64 Module libstdc++.so.6 from deb gcc-14-14.2.0-19.amd64 Module libzstd.so.1 from deb libzstd-1.5.7+dfsg-1.amd64 Stack trace of thread 1071230: #0 0x00007fbd1ca9f95c n/a (libc.so.6 + 0x9495c) #1 0x00007fbd1ca4acc2 raise (libc.so.6 + 0x3fcc2) #2 0x00007fbd1ca334ac abort (libc.so.6 + 0x284ac) #3 0x00007fbd1cc6caa0 n/a (libdovecot.so.0 + 0x6caa0) #4 0x00007fbd1cd49e67 n/a (libdovecot.so.0 + 0x149e67) #5 0x00007fbd1cc6c3d0 i_panic (libdovecot.so.0 + 0x6c3d0) #6 0x00007fbd1c42f942 n/a (lib95_imap_sieve_plugin.so + 0x4942) #7 0x00007fbd1c431223 n/a (lib95_imap_sieve_plugin.so + 0x6223) #8 0x00007fbd1d258f10 n/a (libdovecot-storage.so.0 + 0x11bf10) #9 0x00007fbd1d1a843b mailbox_save_alloc (libdovecot-storage.so.0 + 0x6b43b) #10 0x00005590b7ed4a69 n/a (n/a + 0x0) ELF object binary architecture: AMD x86-64 -- Christian Kivalo

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LDAP AD Quota override not working
by wt.forsaken＠gmail.com 26 Feb '26

26 Feb '26

Hi there, I'm testing the new version of Dovecot 2.4 in Debian 13 before upgrading to my customers and I'm having difficult on trying to override the user's quota. The LDAP base is from Samba4 AD and having been trying the following configuration: auth-ldap.conf.ext: ldap_uris = ldap://localhost ldap_auth_dn = cn=admin,dc=localdomain ldap_auth_dn_password = password ldap_base = ou=users, dc=localdomain passdb ldap { filter = (&(objectClass=person)(sAMAccountName=%{user})) bind = yes fields { userdb_quota_storage_size = %{ldap:telephoneNumber}B } } userdb prefetch { driver = prefetch } userdb ldap { fields { quota_storage_size = %{ldap:telephoneNumber}B } } 90-quota.conf mail_plugins { quota = yes } quota "User quota" { } quota_storage_size = 40M Since there is no quotaBytes in Samba AD, I'm testing to map the telephoneNumber parameters to override the quota, also I'm just testing a 40M to see how it works. Roundcube webmail can see the quota being overriden in its inferior bar, but when I send an email to the user which is above the quota, the journal log inform "failed to store into mailbox 'INBOX': Quota exceeded (mailbox for user is full)". I don't know how to override the quota, since in passdb section I used the "userdb_" prefix but it is not being passed to userdb when I input the "doveadm user ..." command. I don't know if I have been clear in my request, but I'd appreciate any help.

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