==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 0.9.7
- Deployed with iRedMail Easy or the downloadable installer? from FreeBSD ports
- Linux/BSD distribution name and version: FreeBSD 11.1-RELEASE
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? no
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====
I got weird problem: cannot login to accounts in Roundcube (all other IMAP/POP3 clients works ok).
In roundcube logs I see:
[24-Feb-2021 09:24:38 +0000]: <msbks13p> Failed login for user@domain from 7.9.7.5 in session msbks13p3
f7buj6rn000ieid82 (error: -2)

In SQL log:
[24-Feb-2021 09:24:37 +0000]: <msbks13p> [1] SELECT `vars`, `ip`, `changed`, now() AS ts FROM `session` WHERE
`sess_id` = 'msbks13p3f7buj6rn000ieid82';
[24-Feb-2021 09:24:37 +0000]: <msbks13p> [2] DELETE FROM `session` WHERE `sess_id` = 'msbks13p3f7buj6rn000ieid
82';
[24-Feb-2021 09:24:37 +0000]: <msbks13p> [3] SELECT * FROM `users` WHERE `mail_host` = '' AND `username` = '';
[24-Feb-2021 09:24:38 +0000]: <msbks13p> [4] DELETE FROM `session` WHERE `sess_id` = 'msbks13p3f7buj6rn000ieid
82';
[24-Feb-2021 09:24:38 +0000]: <msbks13p> [5] INSERT INTO `session` (`sess_id`, `vars`, `ip`, `changed`) VALUES
('msbks13p3f7buj6rn000ieid82', 'bGFuZ3VhZ2V8czo1OiJydV9SVSI7dGVtcHxiOjE7c2tpbnxzOjU6ImxhcnJ5IjtyZXF1ZXN0X3Rva
2VufHM6MzI6IjllekIxNmVOSk1JTlBtc0k5QTZtYTh3a0hSRG9iMlVPIjs=', '7.9.7.5', now());

tcpdump at lo0 shows no attempts to connect nor to port 143, nor to port 4190.

I'm confused why there is '' at mail_host and username in SELECT query? What can be wrong?