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

iredmail 1.4.0 MARIADB edition
ran downloaded iRedMail.sh  on Debian buster (ver 10)
PHP 7.3.27-1~deb10u1 (cli) (built: Feb 13 2021 16:31:40) ( NTS )
Zend Engine v3.3.27, Copyright (c) 1998-2018 Zend Technologies
with Zend OPcache v7.3.27-1~deb10u1, Copyright (c) 1999-2018, by Zend Technologies.
mysql Server version: 10.3.27-MariaDB-0+deb10u1 Debian 10
nginx version: nginx/1.14.2

I installed iredmail on a clean debian machine and everything went fine. But logging in on roundcube (with the postmaster account) does not work. Iredadmin: It shows the iredadmin panel but the combi of user and pass are not accepted. Let's say I am sure about the accountname and the password I provided during install; entry in log table of iredadmin has:  "Admin login success"
After checking other things I noticed that there is no postmaster user in the roundcube database.
found almost empty database, one entry in system table was: roundcube-version','2019092900

Here is my install log attached , can anyone tell me what went wrong ?

Update : login iredadmin also fails after a second clean install (even without selecting roundcube for install)  nginx says: /iredadmin/login?msg=LOGIN_REQUIRED