How do I setup iRedMail on a separate Ubuntu droplet and where do I point MX records?

<b>“But I cannot receive any mail.”</b> <br> <br>How do you know? Do the emails get bounced back or do they simply disappear? Is there anything in the error logs? <br> <br>If you have a firewall, make sure to open up the relevant ports.

Final Update: <br> <br>Seems like running iptables -F, and rebooting the droplet again fixed the “not receiving email” issue as well. <br> <br>Thanks for all the help! :)

Okay, so the droplet reboot fixed the 4.3.5 server configuration error, and sending mail works now. But I cannot receive any mail. Possible reasons?

Thanks! <br> <br>The configuration tool returns this: <br> <br>The mail server for mail.example.com accepts mail for mailbox ‘postmaster@mail.example.com’. <br> <br>It also passes everything else. No red flags. <br> <br>I still get this when I try to send email: <br> <br>“SMTP Error (451): Failed to add recipient “someone@email.com” (4.3.5 Server configuration problem).” <br> <br>And any incoming email to the mailbox also does not get received. <br> <br>I tried looking all over the internet, but found no solution to the problem.
<br> <br>Do you know what might be causing that?

To make sure you configured your DNS recoreds correctly, run the <a href=“http://www.webdnstools.com/dnstools/domain_check”>Check Domain Configuration</a> tool.

Thank you for the quick response. <br> <br>So now I: <br>- Installed iredmail on a separate droplet via guide. <br>- Created mail.example.com pointing to that droplet.
<br>- Used mail.example.com as the first virtual domain name during installation. <br>- Added a mail.example.com. MX record with priority 1 in the example.com DNS settings. <br>- Went to /iredmailadmin post installation, and added example.com to the list of domains. (Now I have mail.example.com and example.com in iRedAdmin settings.) <br>- Added a new user@example.com in iredadmin settings. <br> <br>Now whenever I log into roundcube using user@example.com, and try to send email to someone@email.com, I get: <br> <br>SMTP Error (451): Failed to add recipient “someone@email.com” (4.3.5 Server configuration problem). <br> <br>I also cannot receive any mail. <br> <br>Help? Once I get a hang of it, I should be able to figure everything else out. <br>

<b>“Do I need to create something like mail.example.com?”</b> Yes. <br> <br><b>“Also once the installation is done, what DNS records should I add for the example.com domain so that email would work?”</b> <br> <br>If you’re using DigitalOcean’s <a href=“https://www.digitalocean.com/community/articles/how-to-set-up-a-host-name-with-digitalocean”>DNS Manager</a>, you would need to add the following <b>MX record:</b> <code>1 - mail.example.com.</code> (don’t forget the trailing dot).