==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.6.3
- Deployed with iRedMail Easy or the downloadable installer? downloadable installer
- Linux/BSD distribution name and version: Debian 11
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):  MySQL
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? Yes
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Mail folder is shared via RoundCube interface.

https://prnt.sc/RCR7zkb1eW7J

And seems somehow shared in Dovecot

root@mail:/var/vmail/vmail1/zim-service.ru/andrey.matveev/Maildir# doveadm acl get -u andrey.matveev@zim-service.ru inbox
ID                              Global Rights
user=support@zim-service.ru            lookup read write-seen

root@mail:/var/vmail/vmail1/zim-service.ru/andrey.matveev/Maildir# doveadm acl debug -u support@zim-service.ru Shared/andrey.matveev@zim-service.ru
doveadm(support@zim-service.ru): Info: Mailbox 'INBOX' is in namespace 'Shared/andrey.matveev@zim-service.ru/'
doveadm(support@zim-service.ru): Info: Mailbox path: /var/vmail/vmail1/zim-service.ru/andrey.matveev//Maildir
doveadm(support@zim-service.ru): Info: All message flags are shared across users in mailbox
doveadm(support@zim-service.ru): Info: User support@zim-service.ru has rights: lookup read write-seen
doveadm(support@zim-service.ru): Info: Mailbox found from dovecot-acl-list
doveadm(support@zim-service.ru): Info: User andrey.matveev@zim-service.ru found from ACL shared dict
doveadm(support@zim-service.ru): Info: Mailbox Shared/andrey.matveev@zim-service.ru is visible in LIST

MariaDB [vmail]> select * from share_folder;
+-------------------------------+------------------------+-------+
| from_user                     | to_user                | dummy |
+-------------------------------+------------------------+-------+
| andrey.matveev@zim-service.ru | support@zim-service.ru | 1     |
+-------------------------------+------------------------+-------+
1 row in set (0.001 sec)

But I can't see this folder either in Roundcube/SoGo or Thunderbird clients.
(it does not get subscribed to) and can not add this folder by hand

Any hint to get this functionality working? Thanks in advance