imap server not reachable

[onslowcodes]

Steps to reproduce

1. update mail app from the former(2.2.1) version to the latest(2.2.2) on nextcloud version 25.0.2
2. add a new mail account.
3. using port 143 and 25 no certificates
4. When I want to save the settings it says imap server not reachable.
5. from the docker image I can ping and access port 143 directly. using the exact same server name.
6. The imap server is not on the same machine.
7. with version 2.2.1 or 2.2.0 I was still able to add accounts. But now I can not because of the failing imap server test.
8. also checked with tcpdump on the Nextcloud machine and the imap server but there were no packets exchanged between these two when I pushed the save button for the account.

Expected behavior

I expected the mail app to reach the imap server since it is reachable there and online and manully testing proves it is from the docker container.

Actual behavior

It says imap server unreachable, and it is not sending packets to the imap server to actually test.

Mail app version

2.2.2

Mailserver or service

dovecot

Operating system

docker image Linux 3.10.0-1160.59.1.el7.x86_64

PHP engine version

PHP 7.4

Web server

Nginx

Database

MariaDB

Additional info

No response