==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.7.1
- Deployed with iRedMail Easy or the downloadable installer? downloadable installer
- Linux/BSD distribution name and version: Ubuntu 24.04.1
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro?
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====
I have installed iRedMail following linuxbabe.com's excellent tutorial.  Everything works for about 2 minutes, but before I can get to running Amavisd to get my DKIM record, both the admin interface and the user interface shut down reporting "Unable to connect".

This system is running on a dedicated server with a clean install of Ubuntu 24.04.1 server.

Here is the mail log:
2024-11-11T13:18:37.213109+00:00 mail postfix/postfix-script[1672]: starting the Postfix mail system
2024-11-11T13:18:37.397958+00:00 mail postfix/master[1674]: daemon started -- version 3.8.6, configuration /etc/postfix
2024-11-11T13:18:46.386387+00:00 mail amavis[832]: starting. /usr/sbin/amavisd at mail.example.com amavis-2.13.0 (20230106), Unicode aware, LANG="en_GB.UTF-8"
2024-11-11T13:18:46.386512+00:00 mail amavis[832]: perl=5.038002, user=988, EUID: 988 (988);  group=(), EGID: 988 988 (988 988)
2024-11-11T13:18:48.160204+00:00 mail amavis[832]: Net::Server: Group Not Defined.  Defaulting to EGID '988 988'
2024-11-11T13:18:48.160370+00:00 mail amavis[832]: Net::Server: User Not Defined.  Defaulting to EUID '988'
2024-11-11T13:18:48.170860+00:00 mail amavis[832]: No ext program for   .F, tried: unfreeze, freeze -d, melt, fcat
2024-11-11T13:18:48.190613+00:00 mail amavis[832]: No ext program for   .zoo, tried: zoo, unzoo
2024-11-11T13:18:48.191013+00:00 mail amavis[832]: No decoder for       .F   
2024-11-11T13:18:48.191098+00:00 mail amavis[832]: No decoder for       .zoo
2024-11-11T13:18:48.191182+00:00 mail amavis[832]: Using primary internal av scanner code for clamav-socket
2024-11-11T13:21:30.198252+00:00 mail postfix/postscreen[3113]: cache btree:/var/lib/postfix/postscreen_cache full cleanup: retained=0 dropped=0 entries
2024-11-11T13:21:30.206024+00:00 mail postfix/postscreen[3113]: CONNECT from [80.94.95.239]:39660 to [<Local_IP>]:25
2024-11-11T13:21:30.238059+00:00 mail postfix/dnsblog[3115]: addr 80.94.95.239 listed by domain zen.spamhaus.org as 127.0.0.9
2024-11-11T13:21:30.238240+00:00 mail postfix/dnsblog[3115]: addr 80.94.95.239 listed by domain zen.spamhaus.org as 127.0.0.4
2024-11-11T13:21:30.238337+00:00 mail postfix/dnsblog[3115]: addr 80.94.95.239 listed by domain zen.spamhaus.org as 127.0.0.2
2024-11-11T13:21:30.238399+00:00 mail postfix/dnsblog[3115]: addr 80.94.95.239 listed by domain zen.spamhaus.org as 127.0.0.3
2024-11-11T13:21:30.245629+00:00 mail postfix/postscreen[3113]: PREGREET 11 after 0.04 from [80.94.95.239]:39660: EHLO User\r\n
2024-11-11T13:21:30.245740+00:00 mail postfix/postscreen[3113]: DISCONNECT [80.94.95.239]:39660
2024-11-11T13:25:29.894253+00:00 mail roundcube: <hmv89c0k> Successful login for user@example.com (ID: 1) fromxx.xx.xx.xx in session hmv89c0k1iud8mda

and the sysylog
2024-11-11T13:25:29.161902+00:00 mail systemd[1]: Starting fwupd.service - Firmware update daemon...
2024-11-11T13:25:29.894253+00:00 mail roundcube: <hmv89c0k> Successful login for user@example.com (ID: 1) fromxx.xx.xx.xx in session hmv89c0k1iud8mda
2024-11-11T13:25:30.119235+00:00 mail dbus-daemon[795]: [system] Activating via systemd: service name='org.freedesktop.UPower' unit='upower.service' requested by ':1.29' (uid=0 pid=3542 comm="/usr/libexec/fwupd/fwupd" label="unconfined")
2024-11-11T13:25:30.155850+00:00 mail systemd[1]: Starting upower.service - Daemon for power management...
2024-11-11T13:25:30.268576+00:00 mail dbus-daemon[795]: [system] Successfully activated service 'org.freedesktop.UPower'
2024-11-11T13:25:30.268746+00:00 mail systemd[1]: Started upower.service - Daemon for power management.
2024-11-11T13:25:30.415890+00:00 mail fwupd[3542]: 13:25:30.415 FuEngine             failed to add device /sys/devices/pci0000:00/0000:00:1f.2/ata5/host4/target4:0:0/4:0:0:0/block/sr0: failed to open /dev/sr0: No medium found
2024-11-11T13:25:30.489291+00:00 mail fwupd[3542]: 13:25:30.489 FuMain               Daemon ready for requests (locale en_GB.UTF-8)
2024-11-11T13:25:30.491501+00:00 mail dbus-daemon[795]: [system] Successfully activated service 'org.freedesktop.fwupd'
2024-11-11T13:25:30.492228+00:00 mail systemd[1]: Started fwupd.service - Firmware update daemon.
2024-11-11T13:25:30.666617+00:00 mail fwupdmgr[3536]: Updating lvfs
2024-11-11T13:25:32.512060+00:00 mail fwupdmgr[3536]: Successfully downloaded new metadata: 0 local devices supported
2024-11-11T13:25:32.520902+00:00 mail systemd[1]: fwupd-refresh.service: Deactivated successfully.

I have UFW set to inactive and nmap indicated that the ports are still open.

Can anyone give me a hint where to look for the reason for the connection failure?

Thanks.