Postfix Issue

Hello All,

I have a problem on my Virtualmin, in particular on Postfix.
In short, when i receive email, form everywhere, it’s going directly into spam folder.

The problem is because my postfix server is not directly on internet but behind a reverse proxy server.

My infrastructure is:


…Nginx proxy 2…Ngnix proxy 1…Nginx proxy 3…

…Hosting Server 1…Hosting Server 2…


Each proxy server have public IP and Internal IP and can reach both Hosting Server on all ports 10000,20000,80,443,25 465,143,993,21
Each hosting server are connected to DBs.

Now problem is, if i put hosting server direct to internet, all email coming right in INBOX, but if i put hosting server Behind Proxies, all email going directly to spam folders.
Now my question is, there is some configuration for trusting proxies server? or problem is on proxy server who maybe masquerade source IP?

Thank you