By "service mlmmjadmin restart", i now followed your advice ...
# service rsyslog restart
# service rsyslog status
● rsyslog.service - System Logging Service
Loaded: loaded (/lib/systemd/system/rsyslog.service; enabled; vendor preset: enabled)
Active: active (running) since Fri 2023-03-17 08:12:11 CET; 8s ago
TriggeredBy: ● syslog.socket
Docs: man:rsyslogd(8)
man:rsyslog.conf(5)
https://www.rsyslog.com/doc/
Main PID: 1942003 (rsyslogd)
Tasks: 4 (limit: 19138)
Memory: 912.0K
CPU: 7ms
CGroup: /system.slice/rsyslog.service
└─1942003 /usr/sbin/rsyslogd -n -iNONE
Mär 17 08:12:11 myserver systemd[1]: Starting System Logging Service...
Mär 17 08:12:11 myserver rsyslogd[1942003]: imuxsock: Acquired UNIX socket '/run/systemd/journal/syslog' (fd 3) from systemd. [v8.2102.0]
Mär 17 08:12:11 myserver systemd[1]: Started System Logging Service.
Mär 17 08:12:11 myserver rsyslogd[1942003]: [origin software="rsyslogd" swVersion="8.2102.0" x-pid="1942003" x-info="https://www.rsyslog.com"] start
... and ...
# service mlmmjadmin restart
# service mlmmjadmin status
● mlmmjadmin.service - RESTful API server used to manage mlmmj myservering list manager
Loaded: loaded (/lib/systemd/system/mlmmjadmin.service; enabled; vendor preset: enabled)
Active: active (running) since Fri 2023-03-17 08:12:41 CET; 5s ago
Process: 1942103 ExecStartPre=/bin/mkdir -p /var/run/mlmmjadmin (code=exited, status=0/SUCCESS)
Process: 1942104 ExecStartPre=/bin/chown mlmmj:mlmmj /var/run/mlmmjadmin (code=exited, status=0/SUCCESS)
Process: 1942105 ExecStartPre=/bin/chmod 0755 /var/run/mlmmjadmin (code=exited, status=0/SUCCESS)
Main PID: 1942106 (uwsgi)
Tasks: 6 (limit: 19138)
Memory: 16.5M
CPU: 107ms
CGroup: /system.slice/mlmmjadmin.service
├─1942106 /usr/bin/uwsgi --ini /opt/mlmmjadmin/rc_scripts/uwsgi/debian.ini --pidfile /var/run/mlmmjadmin/mlmmjadmin.pid
├─1942107 /usr/bin/uwsgi --ini /opt/mlmmjadmin/rc_scripts/uwsgi/debian.ini --pidfile /var/run/mlmmjadmin/mlmmjadmin.pid
├─1942108 /usr/bin/uwsgi --ini /opt/mlmmjadmin/rc_scripts/uwsgi/debian.ini --pidfile /var/run/mlmmjadmin/mlmmjadmin.pid
├─1942109 /usr/bin/uwsgi --ini /opt/mlmmjadmin/rc_scripts/uwsgi/debian.ini --pidfile /var/run/mlmmjadmin/mlmmjadmin.pid
├─1942110 /usr/bin/uwsgi --ini /opt/mlmmjadmin/rc_scripts/uwsgi/debian.ini --pidfile /var/run/mlmmjadmin/mlmmjadmin.pid
└─1942111 /usr/bin/uwsgi --ini /opt/mlmmjadmin/rc_scripts/uwsgi/debian.ini --pidfile /var/run/mlmmjadmin/mlmmjadmin.pid
Mär 17 08:12:41 myserver mlmmjadmin[1942106]: mapped 437616 bytes (427 KB) for 5 cores
Mär 17 08:12:41 myserver mlmmjadmin[1942106]: *** Operational MODE: preforking ***
Mär 17 08:12:41 myserver mlmmjadmin[1942106]: WSGI app 0 (mountpoint='') ready in 0 seconds on interpreter 0x55ec8c564e40 pid: 1942106 (default app)
Mär 17 08:12:41 myserver mlmmjadmin[1942106]: *** uWSGI is running in multiple interpreter mode ***
Mär 17 08:12:41 myserver mlmmjadmin[1942106]: spawned uWSGI master process (pid: 1942106)
Mär 17 08:12:41 myserver mlmmjadmin[1942106]: spawned uWSGI worker 1 (pid: 1942107, cores: 1)
Mär 17 08:12:41 myserver mlmmjadmin[1942106]: spawned uWSGI worker 2 (pid: 1942108, cores: 1)
Mär 17 08:12:41 myserver mlmmjadmin[1942106]: spawned uWSGI worker 3 (pid: 1942109, cores: 1)
Mär 17 08:12:41 myserver mlmmjadmin[1942106]: spawned uWSGI worker 4 (pid: 1942110, cores: 1)
Mär 17 08:12:41 myserver mlmmjadmin[1942106]: spawned uWSGI worker 5 (pid: 1942111, cores: 1)
The error stays the same, but now there is a little more information in /var/log/syslog:
Mar 17 08:14:44 mail iredadmin: [123.45.67.68] GET /iredadmin/profile/maillist/members/list@myserver.mydomain.xy 500 202 "https://myserver.mydomain.xy/iredadmin/search"
Mar 17 08:14:49 mail roundcube: <nq7fiaqh> PHP Error: LDAP: ldap_list failed for dn=domainName=mydomain,o=domains,dc=mydomain,dc=xy. Bad search filter (POST /mail/?_task=mail&_action=autocomplete)