Iredmail Roundcube Not Receiving Email - ubuntu-server

Question

I have my Odoo application running on Ubuntu server 16.04LTS with nginx web server.
I have also installed iredmail and I can access my email account using the domain_name/mail i.e. mgbcomputers.com/mail from where I can send email to another account on my local domain and others like gmail and yahoo.
However when I send an email from my yahoo or gmail to my roundcube email, I get the following error.
This message was created automatically by mail delivery software.
A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:
obabawale#mgbcomputers.com
retry time not reached for any host after a long failure period.
My A/Mx records are correct because i can access my website using the domain address.
Below is my nginx configuration file:
upstream backend-odoo{
server 127.0.0.1:8069;
}
server {
server_name mgbcomputers.com;
listen 80;
add_header Strict-Transport-Security max-age=2592000;
rewrite ^/.*$ https://$host$request_uri? permanent;
}
server {
listen 443 default;
#ssl settings
ssl on;
ssl_certificate /etc/nginx/ssl/server.crt;
# ssl_certificate /etc/ssl/certs/iRedMail.crt;
ssl_certificate_key /etc/nginx/ssl/server.key;
keepalive_timeout 60;
root /var/www/html; #added from iredmail file
index index.php index.html; #added from the iredmail file
# proxy header and settings
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forward-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_redirect off;
# odoo log files
access_log /var/log/nginx/odoo-access.log;
error_log /var/log/nginx/odoo-error.log;
# increase proxy buffer size
proxy_buffers 16 64k;
proxy_buffer_size 128k;
# force timeouts if the backend dies
proxy_next_upstream error timeout invalid_header http_500
http_502 http_503;
# enable data compression
gzip on;
gzip_min_length 1100;
gzip_buffers 4 32k;
gzip_types text/plain application/x-javascript text/xml text/css;
gzip_vary on;
location / {
proxy_pass http://backend-odoo;
}
location ~* /web/static/ {
# cache static data
proxy_cache_valid 200 60m;
proxy_buffering on;
expires 864000;
proxy_pass http://backend-odoo;
}
location /longpolling { proxy_pass http://backend-odoo-im;}
location /mail/ { root /var/vmail/vmail1; } # Added by Lekan for iredmail
# Web applications. Added from iredmail file
#include /etc/nginx/templates/adminer.tmpl; #Added from iredmail file
include /etc/nginx/templates/roundcube.tmpl; #Added from iredmail file
include /etc/nginx/templates/sogo.tmpl; #Added from iredmail file
include /etc/nginx/templates/iredadmin.tmpl; #Added from iredmail file
include /etc/nginx/templates/awstats.tmpl; #Added from iredmail file
# PHP applications. WARNING: php-catchall.tmpl should be loaded after
# other php web applications.
include /etc/nginx/templates/php-catchall.tmpl; #Added from iredmail file
include /etc/nginx/templates/misc.tmpl; #Added from iredmail file
}
upstream backend-odoo-im { server 127.0.0.1:8072; }
What am I not getting here?

Answer 1

If you can access your website, it means that your A record is correct but it does not guarantee that your MX record is also correct. You can try to validate your MX record on this site: https://mxtoolbox.com.
I've checked your domain (mgbcomputers.com) on that site and it's valid with one blacklist record but I think it's also not a problem.
My suggestion, you can try to disable your firewall (ufw) and it's better if you setup your mail server on another server which is specified only for mail service.