Issue Sieve and SSL

[luman]

Server operating system version

Ubuntu 22.04 x86_64

Plesk version and microupdate number

Plesk Obsidian 18.0.51.1

I am trying to access sieve from my local computer. It seems like it is not proper serving any certificate.

❯ openssl s_client -connect mail.myserver.com:4190 -servername mail.myserver.com
CONNECTED(00000003)
40C7A41B9D7F0000:error:0A00010B:SSL routines:ssl3_get_record:wrong version number:ssl/record/ssl3_record.c:354:
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 5 bytes and written 325 bytes
Verification: OK
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
Early data was not sent
Verify return code: 0 (ok)
---

Furthermore, it seems like roundcube is configured to just don't care about certificates:

$config['managesieve_conn_options'] = array(
    'ssl' => array(
    'verify_peer'       => false,
    'verify_peer_name'  => false,
    'allow_self_signed' => true,
    'crypto_method'     => defined('STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT')
                                ? (STREAM_CRYPTO_METHOD_TLS_CLIENT
                                | @STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT
                                | @STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT)
                                : STREAM_CRYPTO_METHOD_SSLv23_CLIENT,
    ),
);

I found this older thread with a similar issue:

Forwarded to devs - Roundcube sieve plugin can´t connect to sieve rules Server

TITLE: Roundcube sieve plugin can´t connect to sieve rules Server PRODUCT, VERSION, OPERATING SYSTEM, ARCHITECTURE: Plesk Onyx for Linux , 17.8.11 MU #1, Ubuntu 16.04.4 LTS, Plesk was updated from 17.5.3 MU #43 to 17.8.11 MU #1 some days ago. PROBLEM DESCRIPTION: If you try to access the sieve...

talk.plesk.com

What am I missing here?