New Mail Server - Can send, but can't receive (550 Unrouteable address)

Community Support Mail
1

Hello Hestia Community,

I’m setting up a new mail server on a fresh Hestia installation and I’ve hit a wall. I would be very grateful for any help.

The Problem: I can send emails perfectly fine from my account ([email protected]) to external addresses like Gmail. I can also log in to Roundcube webmail without any issues.

However, I cannot receive any emails from external addresses. The sender receives a bounce-back email with the error: 550 Unrouteable address.

My Environment:

  • Panel: HestiaCP (latest version)

  • OS: Ubuntu 22.04.5 LTS

  • Mail Server: Exim4 + Dovecot

  • User: mlopesdesign

  • Mail Domain: mlopesdesign.com.br

  • Mail Account: [email protected]

What I’ve Checked (The Key Information):

  1. Firewall is Correct: The Hestia firewall (v-list-firewall) correctly shows that port 25 is open for TCP traffic.

    Plain Text

    RULE  ACTION  PROTO  PORT
----  ------  -----  ----
5     ACCEPT  TCP    25,465,587

  2. Exim is Listening on Port 25:

    Plain Text

    # exim -bP | grep 'daemon_smtp_ports'
daemon_smtp_ports = 25 : 465 : 587

  3. Dovecot User Lookup is Correct: The doveadm user command shows that Dovecot can correctly find the user and its mail path. This proves that Dovecot’s internal configuration is correct.

    Plain Text

    # doveadm user [email protected]
field   value
uid     1002
gid     8
home    /home/mlopesdesign
mail    maildir:/home/mlopesdesign/mail/mlopesdesign.com.br/contato

  4. Exim has Permission to talk to Dovecot: The Debian-exim user is correctly in the mail group.

    Plain Text

    # groups Debian-exim
Debian-exim : Debian-exim mail

  5. File System Permissions are Correct: Based on the doveadm output, I have set the permissions for the mail directory as follows:

    Plain Text

    sudo chown -R mlopesdesign:mail /home/mlopesdesign/mail
sudo chmod -R 770 /home/mlopesdesign/mail

  6. Hestia Rebuild Command Didn’t Work: I have already tried running v-rebuild-mail-domains mlopesdesign, but the issue persists.

Conclusion: Even though:

  • The firewall is open.

  • Exim is listening on the correct port.

  • Dovecot knows the user and the correct mail path.

  • Exim has the permissions to communicate with Dovecot.

  • The file system permissions seem correct.

…Exim is still rejecting incoming mail with 550 Unrouteable address.

This feels like a routing problem deep inside Exim’s configuration that isn’t being resolved by the standard Hestia tools. I’m completely stuck.

Could anyone point me to what I might be missing? Is there a known issue or a specific log file I should be looking at?

Thank you so much for your time and expertise.

2

Hi @mlopesdesign,

That was a bad idea.

Do you know your MX record for your domain is pointing to other mail servers?

❯ dig mlopesdesign.com.br mx +noall +ans
mlopesdesign.com.br.    300     IN      MX      20 mx2.improvmx.com.
mlopesdesign.com.br.    300     IN      MX      10 mx1.improvmx.com.

❯ dig mx1.improvmx.com +noall +ans
mx1.improvmx.com.       3600    IN      A       15.236.236.160
mx1.improvmx.com.       3600    IN      A       13.37.195.136
mx1.improvmx.com.       3600    IN      A       35.181.18.45

❯ dig mx2.improvmx.com +noall +ans
mx2.improvmx.com.       3600    IN      A       13.36.222.39
mx2.improvmx.com.       3600    IN      A       15.236.61.92
mx2.improvmx.com.       3600    IN      A       13.36.107.63

Your MX record should point to mail.mlopesdesign.com.br.

Also, the SPF is authorizing spf.improvmx.com as sender for your domain, I don’t know if you are using them as a smtp relay server. If you are not, you should have to modify the txt records for your domain.

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