Incoming emails are blocked on zimbra. What could be the reason?

Question

iptables

Good afternoon
There are two servers on Centos 7, one is a zimbra server, the second is the main gateway / router. Once a day, incoming on the Zimbra server is blocked. To be treated by restarting the iptables gateway. Blocked steadily in the morning. Checked all running scripts. There is a suspicion on fwrules.sh, but in the logs it says that everything is executed without errors. And it is not clear why everything is treated with a restart. Please help, or which way to look

Answer 1

Little information - which ports are open 443 or 80? Zimbra behind NAT or port forwarding? Do a cron to restart.