==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release):  1.6.2
- Deployed with iRedMail Easy or the downloadable installer? Downloadable installer
- Linux/BSD distribution name and version: Ubuntu 22.10
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): LDAP
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

I am running a testbed iRedMail server on Ubuntu 22.10 and is under testing by my team.  Initially all was well, mails were being tested from application, browsers and mobile.  However about two weeks ago, the machine suddenly stops functioning, email applications such as Outlook / Microsoft mail or even login from web interface does not work.  The mails sent remain in outbox and later gets undelivered. The problem is so much so that even ssh login to the Server does not happen intermittently. Assuming it to be a network problem because even ping to the machine stops, we tried isolating the machine, but later realised it was the issue with one of iRedMail services, because as part of various checks done, we stopped all services on the server such as postfix, dovecot, nginx, slapd and amavis. When we stop these services, the machine starts processing remote ssh login and even the ping to Internet such as Google stabilizes.
However when these services are started back, the machine seems to function alright for about half a day and then the mails stops, no new mails come in or go out, connections don't get established if we are using mail application and ping to local LAN or Internet too stops.
I know there are lot of application in play, but where and which logs do we begin...?

Thanks, Best

BA