[SOLVED] Roundcube SMTP Authentication Error Fix

Support
1

Hello,

I’m sharing this as a fix I found for Roundcube SMTP authentication error.

Freedombox Version: Debian GNU/Linux trixie/sid and FreedomBox version 23.13.
Roundcube Version: Roundcube Webmail 1.6-git

On Debian Testing, if Roundcube is updated, you will likely get an SMTP authentication failure message if trying to send e-mail.

To fix the error, I applied the following.

  1. Edit the Roundcube configuration file with sudo nano /etc/roundcube/config.inc.php
  2. Replace $config['smtp_host'] = 'localhost:587'; with $config['smtp_host'] = 'tls://%n:587';
  3. Exit nano (ctrl+x) and restart apache with sudo systemctl restart apache2

Explanation:
Roundcube requires that smtp tls authentication aligns with your certificate. To provide this, I added tls:// followed by %n to specify my domain.

Hope this helps anyone that comes along.

2 Likes
2

Good stuff man. Everything was working perfectly and then today I noticed that this error popped on me. I’m running Virtualmin 7.10.0 Pro with Ubuntu Linux 22.04.4 and Roundbox 1.6.1

1 Like
3

Sweet! I am running an Ubuntu server and was plagued by botnet smtp auth attempts. So I turned off smtp auth on port 25, and turned on TLS on port 587 but then got the error described above. My config ddn’t work with %n, I had to use
$config[‘smtp_host’] = ‘tls://localhost:587’;
but glad to say it worked!
Thanks for posting!

1 Like
4

I have the same problem as I get

SMTP Error (): Authentication failed.

Changing the line (and restarting apache) to either
$config['smtp_server'] = 'tls://%n:587';
or
$config['smtp_server'] = 'tls://localhost:587';
gives me the same error, thus I cannot longer use roundcube for sending e-mail (using sogo or an e-mail client works).

5

Hi

I’ve had the same error when I first did setup the email server.

This did solve the problem, since Roundcube is on the same server like Postfix/Dovecot:

sudo nano /etc/roundcube/config.inc.php

there change the setting under SMTP host to port 25

$config['smtp_host'] = 'localhost:25';

I have found this solution on the FreedomBox under Apps > Postfix/Dovecot, enlarge the description and you will find it at almost the end of it.

1 Like
6

Thank you your answer. I am afraid, though, that this solution is not acceptable. Using port 25 is a security risk and, also, it can lead to my emails being blocked by recipient servers.

7

Using port 25 is not a security risk in this case, as the communication between Roundcube and the mail server never leaves the server. This won’t make other servers block you.

3 Likes
8

Oh! I didn’t knew that this happens internally. Thank you, both!