Email notification is not sent upon directory share to group of users

[abalage]

Steps to reproduce

1. Create a group of users: foobar
2. Set up email notifications for shared files or directories for every user in group foobar. (either user-by-user or global for new users)
3. Share a directory with group foobar

Expected behaviour

Email notification should be sent to every member of group foobar.

Actual behaviour

No emails are being sent. No connection to SMTP server. (postfix logs checked)

However I also experienced that in case I explicitly add users one by one to the share instead of set the group, email notifications are going to be sent out as expected.

Server configuration

Operating system:
Debian Stretch
Web server:
reverse proxy + backend are both nginx:1.14 official images from docker hub
Database:
mariadb-10.2.15
PHP version:
7.1.20: custom docker image based on official php:7.1-fpm docker image from docker hub
Nextcloud version: (see Nextcloud admin page)
13.0.5.2
Updated from an older Nextcloud/ownCloud or fresh install:
continuously updated from owncloud since the very first version of nextcloud was available
Where did you install Nextcloud from:
Manual install.
Signing status:

Signing status

Login as admin user into your Nextcloud and access 
http://example.com/index.php/settings/integrity/failed 
paste the results here.

List of activated apps:

App list

  - activity: 2.6.1
  - admin_audit: 1.3.0
  - bruteforcesettings: 1.1.0
  - comments: 1.3.0
  - dav: 1.4.7
  - federatedfilesharing: 1.3.1
  - federation: 1.3.0
  - files: 1.8.0
  - files_external: 1.4.1
  - files_pdfviewer: 1.2.1
  - files_sharing: 1.5.0
  - files_texteditor: 2.5.1
  - files_trashbin: 1.3.0
  - files_versions: 1.6.0
  - files_videoplayer: 1.2.0
  - firstrunwizard: 2.2.1
  - gallery: 18.0.0
  - impersonate: 1.0.4
  - logreader: 2.0.0
  - lookup_server_connector: 1.1.0
  - nextcloud_announcements: 1.2.0
  - notifications: 2.1.2
  - oauth2: 1.1.1
  - password_policy: 1.3.0
  - provisioning_api: 1.3.0
  - registration: 0.4.2
  - serverinfo: 1.3.0
  - sharebymail: 1.3.0
  - survey_client: 1.1.0
  - systemtags: 1.3.0
  - theming: 1.4.5
  - twofactor_backupcodes: 1.2.3
  - updatenotification: 1.3.0
  - workflowengine: 1.3.0
Disabled:
  - encryption
  - files_downloadactivity
  - spreed
  - user_external
  - user_ldap

Nextcloud configuration:

Config report

{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "***REMOVED SENSITIVE VALUE***",
            "***REMOVED SENSITIVE VALUE***"
        ],
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "forwarded_for_headers": [
            "HTTP_X_FORWARDED_FOR",
            "HTTP_X_REAL_IP"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "overwrite.cli.url": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "13.0.5.2",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "logtimezone": "UTC",
        "installed": true,
        "filelocking.enabled": true,
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 6379,
            "timeout": 0,
            "password": "***REMOVED SENSITIVE VALUE***"
        },
        "memcache.local": "\\OC\\Memcache\\APCu",
        "mail_smtpmode": "smtp",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "25",
        "trashbin_retention_obligation": "1",
        "default_language": "hu_HU",
        "cache_path": "\/var\/tmp\/",
        "loglevel": 1,
        "theme": "",
        "maintenance": false,
        "updater.release.channel": "stable",
        "updater.secret": "***REMOVED SENSITIVE VALUE***"
    }
}

Are you using external storage, if yes which one: local/smb/sftp/...
local
Are you using encryption: yes/no
no
Are you using an external user-backend, if yes which one: LDAP/ActiveDirectory/Webdav/...
no

Client configuration

Browser:
Firefox 61
Operating system:
openSUSE Leap 15

Logs

Web server error log

Web server error log

sorry.. nope. there are nothing exciting

Nextcloud log (data/nextcloud.log)

Nextcloud log

sorry... nope. there are nothing exciting or exception compared to normal usage

Browser log

Browser log

let me know if this is really a must

[nextcloud-bot]

GitMate.io thinks possibly related issues are #9536 (email notifications not sending), #5658 (share by email - password email not sent - solved), #5047 (Can't password protect shares because password email is sent from account email address), #2931 (No notification send for upload on public share), and #1762 ([Feature] send a file to user (not sharing)).

[rullzer]

@nextcloud/sharing @nickvergessen

[nickvergessen]

This is not related to notifications/activity
But about the sharing internal email I guess?

[sourabhsaha1989]

I also have the same problem. Can Someone provide any solution???

[wiswedel]

Can still be reproduced in 18b2

[wiswedel]

Can still be reproduced in 18b2

Problem still persists in 18b3

CC @nextcloud/server-triage

[wiswedel]

This bug is still present in 18.0.0. Can anyone please pick this up urgently? @nextcloud/server-triage

[rullzer]

We never had direct e-mails for group shares.
But once cron ran you should get an activity mail at some point.

[szaimen]

Is this Issue still valid in NC21.0.2? If not, please close this issue. Thanks! :)

[ghost]

This issue has been automatically marked as stale because it has not had recent activity and seems to be missing some essential information. It will be closed if no further activity occurs. Thank you for your contributions.