"Sendmail" option not available

Steps to reproduce

  1. Install Owncloud.
  2. As an admin, go to Settings > Admin > General
  3. In the the “Email Server” section, open the “Send Mode” list.

Expected behaviour

According to the documentation, there should be “Sendmail”, “qmail”, “php” and “smtp” in the list.

Actual behaviour

There is only PHP in the list.

Note

PHP is running in chrooted mode.
I am using this fork of mini_sendmail : https://github.com/vkucukcakar/mini_sendmail

I also tried to use the PHP method, but it does not work.

Server configuration

Operating system:
Debian 10
Web server:
Nginx 1.18
Database:
MariaDB 10.3.22
PHP version:
FPM 7.3
ownCloud version: (see ownCloud admin page)
10.5.0.10
Updated from an older ownCloud or fresh install:
Fresh Install
Where did you install ownCloud from:

Signing status (ownCloud 9.0 and above):

No errors have been found.

The content of config/config.php:

{
    "basic": {
        "license key": "***REMOVED SENSITIVE VALUE***",
        "date": "Mon, 31 Aug 2020 16:19:51 +0000",
        "ownCloud version": "10.5.0.10",
        "ownCloud version string": "10.5.0",
        "ownCloud edition": "Community",
        "server OS": "Linux",
        "server OS version": "Linux ***REMOVED SENSITIVE VALUE*** 4.19.0-9-amd64 #1 SMP Debian 4.19.118-2+deb10u1 (2020-06-07) x86_64",
        "server SAPI": "fpm-fcgi",
        "webserver version": "nginx\/1.18.0",
        "hostname": "***REMOVED SENSITIVE VALUE***",
        "logged-in user": "***REMOVED SENSITIVE VALUE***"
    },
    "stats": {
        "users": {
            "Database": {
                "count": 1,
                "seen": 1,
                "logged in (30 days)": 1
            }
        },
        "groups": {
            "OC\\Group\\Database": 1
        }
    },
    "config": {
        "instanceid": "ocnxdyb23ceh",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "cloud.gbweb.fr"
        ],
        "datadirectory": "\/var\/www\/***REMOVED SENSITIVE VALUE***\/public_html\/owncloud\/data",
        "overwrite.cli.url": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "10.5.0.10",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "localhost",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "logtimezone": "UTC",
        "loglevel": "1",
        "apps_paths": [
            {
                "path": "\/var\/www\/***REMOVED SENSITIVE VALUE***\/public_html\/owncloud\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/var\/www\/***REMOVED SENSITIVE VALUE***\/public_html\/owncloud\/apps-external",
                "url": "\/apps-external",
                "writable": true
            }
        ],
        "installed": true,
        "mail_smtpmode": "php",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "25",
        "mail_smtptimeout": 10,
        "mail_smtpauthtype": "LOGIN",
        "mail_smtpdebug": true,
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***"
    },
    "integritychecker": {
        "passing": true,
        "enabled": true,
        "result": []
    },
    "core": {
        "backgroundjobs_mode": "cron",
        "first_install_version": "10.5.0.10",
        "installedat": "1598807569.0449",
        "lastcron": "1598889675",
        "lastupdateResult": "[]",
        "lastupdatedat": "1598890780",
        "public_files": "files_sharing\/public.php",
        "public_webdav": "dav\/appinfo\/v1\/publicwebdav.php"
    },
    ... (too long for a post)

List of activated apps:

None

Are you using external storage, if yes which one: No

Are you using encryption: No

Are you using an external user-backend, if yes which one: No

Logs

Web server error log

None

ownCloud log (data/owncloud.log)

Sadly, None

Browser log

Deprecation warning: tipsy is deprecated. Use tooltip instead. js.js:2320:10
Erreur dans les liens source : Error: JSON.parse: unexpected character at line 1 column 1 of the JSON data
URL de la ressource : https://cloud.gbweb.fr/core/vendor/jquery/dist/jquery.min.js?v=156c1a1cd2fc4710f74b3613142c96e9
URL du lien source : jquery.min.map

Hey,

i have searched through the source code of ownCloud like https://github.com/owncloud/core/search?q=sendmail&unscoped_q=sendmail and found the following:

If i’m understanding this code correctly ownCloud requires a “sendmail” binary on your system which needs to be accessible to ownCloud so that the sendmail option is showing up.