# Roundcube sending messages causes "SMTP Error"
**URL:** https://forum.yunohost.org/t/roundcube-sending-messages-causes-smtp-error/43269
**Category:** Support
**Tags:** english
**Created:** [October 28, 2026, 11:36pm UTC](https://forum.yunohost.org/t/roundcube-sending-messages-causes-smtp-error/43269 "2026-10-28T23:36:04Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@brainchild](https://forum.yunohost.org/u/brainchild)
#### Post date: [October 28, 2026, 11:36pm UTC](https://forum.yunohost.org/t/roundcube-sending-messages-causes-smtp-error/43269/1 "2026-10-28T23:36:04Z")
# Environment
- **Application:** Roundcube 1.7.5~ynh1
- **Yunohost version:** 13.0.8 (testing)
- **Hardware:** Cloud VPS, x86
# Description
As I have been trying to use Roundcube, I have unfortunately encountered a variety of problems.
One serious problem has been a complete failure to send any outgoing messages.
When it is attempted to send a message from the composition pane (by clicking the button _Send_), no action is completed, instead only is briefly flashed, in the lower right corner of the pane, the following error message:
> SMTP Error (): Connection to server failed.
Despite that my testing so far has been quite limited, I recall at least having some previous success in sending basic outgoing messages.
Additionally, forwarded messages have reached their destinations, through the same channels.
I would like help resolving the cause of the 'SMTP Error".
# Notes
It is possible that the more suitable category would be _Support apps_, in comparison to _Support_.
Additionally, the problem as reported seems to be a duplicate of the topic referenced below, but no resolution has been offered that preserves the model of low-level administration being subsumed under the broader automated framework of Yunohost.
* * *
> [@Roundcube - SMTP Error (): Connection to server failed](https://forum.yunohost.org/t/40138):
>
> Roundcube Webmail 1.6.11 Yunohost 12.0.17 Roundcube was working ok, but not now. Now users cannot send email, they get: SMTP Error (): Connection to server failed Sending emails keeps working ok if managed through regular clients. I reinstalled Roundcube to see if that fixed it, it did not. What should I do? Is there any logs I should check? Cannot find them. Thank you
---
### Author:  [@ljf](https://forum.yunohost.org/u/ljf)
#### Post date: [October 29, 2026, 10:36am UTC](https://forum.yunohost.org/t/roundcube-sending-messages-causes-smtp-error/43269/2 "2026-10-29T10:36:17Z")
Could you check that the domain setting `mail_out` is activated `Web Admin > Domains > XXXX.tld > Outgoing emails` ?
You probably should open the mail log (see bellow) and retry to send a mail with roundcube to see if something appears in the log:
```auto
tail -f /var/log/mail.log
```
(do CTRL + C to terminate this command)
* * *
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---
### Author:  [@jarod5001](https://forum.yunohost.org/u/jarod5001)
#### Post date: [October 29, 2026, 5:30pm UTC](https://forum.yunohost.org/t/roundcube-sending-messages-causes-smtp-error/43269/3 "2026-10-29T17:30:15Z")
The user must have mail permission or in a group that has mail permission
---
### Author:  [@brainchild](https://forum.yunohost.org/u/brainchild)
#### Post date: [October 30, 2026, 12:55am UTC](https://forum.yunohost.org/t/roundcube-sending-messages-causes-smtp-error/43269/5 "2026-10-30T00:55:36Z")
I can confirm that outgoing mail is enabled for the domain, based on reviewing the configuration menus to which you referred.
Thank you, also, for your suggestion to review the mail log.
Unfortunately, I find nothing of interest relating to my attempt to send a message through Roundcube:
As follows is a (redacted) except of `/var/log/mail.log`:
```none
postfix/submission/smtpd[146179]: connect from unknown[1234:abcd::]
postfix/submission/smtpd[146179]: TLS SNI yunohost.example.tld from unknown[1234:abcd::] not matched, using default chain
postfix/submission/smtpd[146179]: Anonymous TLS connection established from unknown[1234:abcd::]: TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (4096 bits) server-digest SHA256
postfix/submission/smtpd[146179]: NOQUEUE: lost connection after STARTTLS from unknown[1234:abcd::]
postfix/submission/smtpd[146179]: disconnect from unknown[1234:abcd::] ehlo=1 starttls=1 commands=2
```