Hello all,
I am not fit enough to find the reason, why the smtp access to our mailcow server goes down on a regular basis (every 2 to 3 days). A restart of the server maschine solves the problem.
I found error in the log webinteface under Postfix. Thanks a lot for any ideas !

Here our system info:
Container information
acme-mailcow (mailcow/acme:1.82) (Started on 07.08.2022, 11:33:04)
dockerapi-mailcow (mailcow/dockerapi:1.42) (Started on 07.08.2022, 11:32:55)
dovecot-mailcow (mailcow/dovecot:1.17) (Started on 07.08.2022, 11:33:08)
ipv6nat-mailcow (robbertkl/ipv6nat) (Started on 07.08.2022, 11:32:52)
memcached-mailcow (memcached:alpine) (Started on 07.08.2022, 11:32:58)
mysql-mailcow (mariadb:10.5) (Started on 07.08.2022, 11:33:10)
netfilter-mailcow (mailcow/netfilter:1.48) (Started on 07.08.2022, 11:32:52)
nginx-mailcow (nginx:mainline-alpine) (Started on 07.08.2022, 11:33:08)
ofelia-mailcow (mcuadros/ofelia:latest) (Started on 07.08.2022, 11:33:02)
olefy-mailcow (mailcow/olefy:1.10) (Started on 07.08.2022, 11:33:08)
php-fpm-mailcow (mailcow/phpfpm:1.79) (Started on 07.08.2022, 11:32:56)
postfix-mailcow (mailcow/postfix:1.67) (Started on 07.08.2022, 11:33:08)
redis-mailcow (redis:6-alpine) (Started on 07.08.2022, 11:33:08)
rspamd-mailcow (mailcow/rspamd:1.90) (Started on 07.08.2022, 11:32:57)
sogo-mailcow (mailcow/sogo:1.109) (Started on 07.08.2022, 11:33:08)
unbound-mailcow (mailcow/unbound:1.16) (Started on 07.08.2022, 11:32:55)
watchdog-mailcow (mailcow/watchdog:1.96) (Started on 07.08.2022, 11:32:57)