Rails how to just receive emails through action mailbox?

I am currently testing and setting up an email service system.

I just need to be able to receive emails ， but no need to send email.

1. my dns mail.xxx.com is ping successful, it can get bytes from IP address.

2. My online-server had open port： 443，25, 587

3. I used docker to deploy my rails server.

   Dockers proxy ports is: 443，25, 587 and rails server port is 3005

4. My ApplicationMailbox and comments_mailbox like this:

class ApplicationMailbox < ActionMailbox::Base
  
  #routing /@xxx.com/i => :comments
  routing :all => :comments
end

class CommentsMailbox < ApplicationMailbox
  def process
    p mail.decoded
  rescue => e 
    p e
  end
end

4. My nginx configuration is like this:

user xxx;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;
events {
  worker_connections 1024;
}

http {
  ...

location ~ /(api|rails)/ {
                proxy_pass http://127.0.0.1:3005;
                proxy_set_header X-Real-IP       $remote_addr;
                proxy_set_header X-Forwarded-For 
                $proxy_add_x_forwarded_for;
                proxy_set_header  HTTP_X_FORWARDED_FOR $remote_addr;
                proxy_set_header NginX-Proxy   true;
                proxy_set_header X-Forwarded-Proto $scheme;
                proxy_set_header Host $http_host;
                proxy_redirect off;
                autoindex_exact_size on;
                autoindex_localtime on;
                proxy_read_timeout 240s;
          }
...
}

When I send email from gmail account to ydddd@xxx.com (my custom emails), I can't receive email in production.

What's wrong with it? Could you please help me? Thanks so much~~

Supplement:

I had read this answer and article: https://stackoverflow.com/questions/58326314/postfix-setup-for-action-mailbox/61629911#61629911

https://thedevpost.com/blog/setup-action-mailbox-with-postfix-part-2/

It is greate.

but I'm sorry that I also cannot receive the email.

This is my custom cofiguration:

# /usr/local/bin/email_forwarder.sh

#!/bin/sh
export HOME=/home/airdrop
export PATH=/home/airdrop/.rvm/bin
export RVM_ROOT=/home/airdrop/.rvm/bin/rvm
cd /home/airdrop && bin/rails action_mailbox:ingress:postfix URL='http://localhost:3005/rails/action_mailbox/relay/inbound_emails' INGRESS_PASSWORD='xxxxxxx'

# /etc/postfix/virtual_aliases

@xxx.com  airdrop@xxx.com

# /etc/postfix/transport

xxx.com    forward_to_rails:

# /etc/postfix/master.cf

...
forward_to_rails   unix  -       n       n       -       -       pipe
  flags=Xhq user=airdrop:airdrop argv=/usr/local/bin/email_forwarder.sh
  ${nexthop} ${user}

Then I restart the postfix sudo service postfix restart, it runs ok.

When I send Email from gmail to ydddd@xxx.com (my custom emails), I can not receive any mail.log, also can not reach to my rails action mailer.

What's wrong with it? Could you please help me? Thanks so much~~