No email is sent to attendees when event is created on a shared calendar.

[LalunePierr0t]

Steps to reproduce

1. Create a event on a shared calendar
2. Add some attendees by email

Expected behaviour

The attendees receive an invitation

Actual behaviour

The attendees do not receive any invitation

Calendar app

Client configuration

Browser: (e.g. Firefox 48)
Firefox 87.0

Operating system: (e.g. Arch Linux)
Ubuntu 20.04

Server configuration

Operating system: (e.g. Debian 8)
sb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.5 LTS
Release: 18.04
Codename: bionic

Web server: (e.g. Apache, Nginx,...)

Database: (e.g. MariaDB, SQLite or PostgreSQL)

PHP version: (e.g. 7.0.3)

Nextcloud Version: (see admin page, e.g. 17.0.2)
Nextcloud 20.0.8
Snap install

Updated from an older installed version or fresh install:

List of activated apps:

sudo nextcloud.occ app:list
Enabled:
  - accessibility: 1.6.0
  - activity: 2.13.4
  - apporder: 0.12.0
  - bookmarks: 4.1.0
  - calendar: 2.2.0
  - carnet: 0.23.8
  - cloud_federation_api: 1.3.0
  - comments: 1.10.0
  - contactsinteraction: 1.1.0
  - dashboard: 7.0.0
  - dav: 1.16.2
  - deck: 1.2.7
  - documentserver_community: 0.1.9
  - epubreader: 1.4.5
  - extract: 1.3.1
  - federatedfilesharing: 1.10.2
  - federation: 1.10.1
  - files: 1.15.0
  - files_pdfviewer: 2.0.1
  - files_rightclick: 0.17.0
  - files_sharing: 1.12.2
  - files_trashbin: 1.10.1
  - files_versions: 1.13.0
  - files_videoplayer: 1.9.0
  - firstrunwizard: 2.9.0
  - forms: 2.2.4
  - logreader: 2.5.0
  - lookup_server_connector: 1.8.0
  - mail: 1.9.5
  - nextcloud_announcements: 1.9.0
  - notifications: 2.8.0
  - oauth2: 1.8.0
  - onlyoffice: 6.3.0
  - password_policy: 1.10.1
  - polls: 1.8.1
  - privacy: 1.4.0
  - provisioning_api: 1.10.0
  - recommendations: 0.8.0
  - registration: 1.2.1
  - serverinfo: 1.10.0
  - settings: 1.2.0
  - sharebymail: 1.10.0
  - spreed: 10.0.7
  - support: 1.3.0
  - survey_client: 1.8.0
  - systemtags: 1.10.0
  - twofactor_backupcodes: 1.9.0
  - unsplash: 1.2.2
  - user_status: 1.0.1
  - viewer: 1.4.0
  - weather_status: 1.0.0
  - workflowengine: 2.2.0
Disabled:
  - admin_audit
  - drawio
  - encryption
  - files_external
  - photos
  - text
  - theming
  - user_ldap

Nextcloud configuration:

sudo nextcloud.occ config:list system
{
    "system": {
        "apps_paths": [
            {
                "path": "\/snap\/nextcloud\/current\/htdocs\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/var\/snap\/nextcloud\/current\/nextcloud\/extra-apps",
                "url": "\/extra-apps",
                "writable": true
            }
        ],
        "supportedDatabases": [
            "mysql"
        ],
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "memcache.local": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 0
        },
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "51.178.139.118",
            "nuagederochefort.xyz",
            "128.127.17.1"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "20.0.8.1",
        "overwrite.cli.url": "https:\/\/nuagederochefort.xyz",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "mail_smtpmode": "smtp",
        "mail_smtpsecure": "ssl",
        "mail_sendmailmode": "smtp",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "465",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpauthtype": "LOGIN",
        "maintenance": false,
        "skeletondirectory": "",
        "default_locale": "fr_FR",
        "has_rebuilt_cache": true,
        "mail_smtpauth": 1,
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "loglevel": 0,
        "theme": "",
        "app_install_overwrite": [
            "registration",
            "documentserver_community"
        ]
    }
}

Logs

Web server error log (e.g. /var/log/apache)

Insert your webserver log here

Log file (data/nextcloud.log)

Insert your nextcloud.log file here

Browser log

Insert your browser log here, this could for example include:

a) The javascript console log
b) The network log
c) ...

[tcitworld]

See nextcloud/server#26668 (and linked issues for details)