Cannot send email via SMTP

Server
1

I am trying to use the SMTP functionality without success and I cannot understand what is going wrong.

The credentials work with other systems (from Python to other services that use SMTP).

I tried multiple authentications (Login, Plain, None) and different encyptions, but the error returned is always the same.

I tried to enable the debug but I did not received additional information at all.

Is anyone able to help me?

Thanks

Steps to reproduce

  1. Open Settings/General

  2. Insert SMTP data

  3. Try to send email

Expected behaviour

I expect the email to be sent.

Actual behaviour

An error is returned:

image
image1598×401 26.8 KB

Server configuration

Operating system:

Web server:

Database:

PHP version:

ownCloud version: 10.15.3.0 Community

Updated from an older ownCloud or fresh install: fresh install

Where did you install ownCloud from: Docker

The content of config/config.php:

  'mail_smtphost' => 'mail.smtp2go.com',
  'mail_smtpport' => '2525',
  'mail_smtpdebug' => true,
  'mail_smtpsecure' => 'tls',
  'mail_smtpauth' => 1,
  'mail_smtpname' => 'My email user',
  'mail_smtppassword' => 'My password',
  'mail_smtpauthtype' => 'LOGIN',

Client configuration

Browser: Brave

Operating system: Win 11

Logs

Web server error log

Insert your webserver log here

ownCloud log (data/owncloud.log)

[24/Aug/2025:12:12:42 +0200] "POST /settings/admin/mailtest HTTP/1.1" 200 1003 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Safari/537.36"

Browser log

no log