==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.1
- Deployed with iRedMail Easy or the downloadable installer? Downloadable installer
- Linux/BSD distribution name and version: Ubuntu 18.04 LTS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): PGSQL
- Web server (Apache or Nginx):Nginx
- Manage mail accounts with iRedAdmin-Pro? Yes
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

I have one very important organization that our organization must communicate with via email. Sometime last week, emails to this one organization started timing out, only I was not aware. Last Wednesday I sent an email and I got the timeout message today, 5 days later. The last time I had to email someone there was in June and it worked fine. So, I have 2 questions:

1. Where do I set this timeout value so that I get the error within minutes instead of days?
2. Where do I look to start troubleshooting? That is, what logs and is there any phrase I should look for?

Thanks