This feature is essential in any professional mail server.
The reputation of a mail server is very important so that emails reach the recipient's inbox and not the spam box. It´s vital.
If you want to use the cloudron mail server in a professional way to send thousands and thousands of emails from different clients (emails that you cannot control), it is necessary to be able to monitor the percentage of bounces and percentage of complaints (spam) to take care of the server health .
If a client sends a lot of emails with our Cloudron mail server using bad practices (purchased databases, for example), by increasing complaints and bounces, it will considerably damage the reputation of our mail server. This can cause us to block the domain of the server for sending emails, with its corresponding consequences.
I propose to implement in the cloudron mail server the monitoring and control of those bounce and complaint rates associated with each sender email, that is, the email that caused those bounces and complaints. In such a way, that our cloudron mail server could automatically block the sending of emails with that sender if it exceeds certain limits / percentages that we must define.
For example, Amazon SES has a 5% bounce limit and a 0.1% complaint limit. Here you can see how Amazon has implemented this: https://prnt.sc/10apcxh
In addition, administrators should be notified by email when the mail server detects a rapid increase of these 2 percentages in a sender, and we can also block that sender manually.
Having a graph would help a lot to detect problemas before they happen: https://prnt.sc/10aq1l5
I am not an expert in mail servers, but an expert in this forum could confirm if what I say is that important or not.
In short: this would be to enable an effective control of the Mail Server Health. Something super important that would give Cloudron's mail server much more value over the rest of the competition. An important factor that would help more people to decide to use Cloudron.