This is likely related to the recent roundcube updates but I never tried sending until read mail was fixed.
```
# dpkg -l roundcubemail
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-===============================================-============================-============================-====================================================================================================
ii roundcubemail 1:1.5.3-0~kolab2 all skinnable AJAX based webmail solution for IMAP servers
```
I thought I had carried all my old config options forward during the update but I am getting SMTP authentication errors when I try and send mail from the web interface.
From roundcube/errors.log
```
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> PHP Error: STARTTLS failed (POST /webmail/QWxUhrcFcDdMwDOk/?_task=mail&_unlock=loading1672857351125&_framed=1&_action=send)
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> PHP Error: Invalid response code received from server (POST /webmail/QWxUhrcFcDdMwDOk/?_task=mail&_unlock=loading1672857351125&_framed=1&_action=send)
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> SMTP Error: Authentication failure: STARTTLS failed (Code: ) in /usr/share/roundcubemail/program/lib/Roundcube/rcube.php on line 1778 (POST /webmail/QWxUhrcFcDdMwDOk/?_task=mail&_unlock=loading1672857351125&_framed=1&_action=send)
```
and from roundcube/smtp.log:
```
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Connecting to tls://mail.domain.tld:587...
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv: 220 mail.domain.tld ESMTP Postfix (Ubuntu)
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Send: EHLO mail.domain.tld
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv: 250-mail.domain.tld
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv: 250-PIPELINING
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv: 250-SIZE 52428800
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv: 250-VRFY
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv: 250-ETRN
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv: 250-STARTTLS
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv: 250-ENHANCEDSTATUSCODES
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv: 250-8BITMIME
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv: 250-DSN
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv: 250 SMTPUTF8
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Send: STARTTLS
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv: 220 2.0.0 Ready to start TLS
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Send: QUIT
[04-Jan-2023 13:35:51 -0500]: <dgdf2s4d> Recv:��j
```
From config.inc.php:
```
$config['smtp_server'] = 'tls://%n';
// SMTP port. Use 25 for cleartext, 465 for Implicit TLS, or 587 for STARTTLS (default)
$config['smtp_port'] = 587;
// SMTP username (if required) if you use %u as the username Roundcube
// will use the current username for login
$config['smtp_user'] = '%u';
// SMTP password (if required) if you use %p as the password Roundcube
// will use the current user's password for login
$config['smtp_pass'] = '%p';
```