Updates on events in calender will not be sent to invitees

[linuxpete]

Steps to reproduce

1. Make an event and add attendees
2. Owncloud sends e-mail to attendees
3. Change same event and press "accept" 4 Owncloud does not send e-mail to attendees

Expected behaviour

When changes to event are being made attendees receive an update

Actual behaviour

No update is being send

Serve

r configuration Operating system: Raspbian

Web server: Nginx

Database: Mysql

PHP version: 5.6.29

Server version: (see your admin page) 9.1.3

Calendar version: (see the apps page) 1.4.1

Updated from an older installed version or fresh install: Updated 8.x

Signing status (ownCloud/Nextcloud 9.0 and above):

Login as admin user into your cloud and access 
No errors have been found.
paste the results here.

List of activated apps:

If you have access to your command line run e.g.:
  - activity: 2.3.2
  - bookmarks: 0.9.0
  - calendar: 1.4.1
  - comments: 0.3.0
  - contacts: 1.5.1
  - dav: 0.2.7
  - documents: 0.13.1
  - external: 1.2
  - federatedfilesharing: 0.3.0
  - federation: 0.1.0
  - files: 1.5.1
  - files_antivirus: 0.9.0.0
  - files_external: 0.6.0
  - files_pdfviewer: 0.8.1
  - files_reader: 0.7.2
  - files_sharing: 0.10.0
  - files_texteditor: 2.1
  - files_trashbin: 0.9.0
  - files_versions: 1.3.0
  - files_videoplayer: 0.9.8
  - firstrunwizard: 1.1
  - gallery: 15.0.0
  - gpxpod: 0.9.16
  - music: 0.3.12
  - notifications: 0.3.0
  - ownnote: 1.08
  - provisioning_api: 0.5.0
  - shorten: 0.0.15
  - systemtags: 0.3.0
  - tasks: 0.9.4
  - templateeditor: 0.1
  - updatenotification: 0.2.1
Disabled:
  - audioplayer
  - encryption
  - files_gpxviewer_extended-master
  - user_external
  - user_ldap

from within your instance's installation folder

The content of config/config.php:

If you have access to your command line run e.g.:
sudo -u www-data php occ config:list system
from within your instance's installation folder

or 

Insert your config.php content here
(Without the database password, passwordsalt and secret)

Are you using external storage, if yes which one: local/smb/sftp/... /mnt/owncloud

Are you using encryption: yes/no no

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

LDAP configuration (delete this part if not used)

With access to your command line run e.g.:
sudo -u www-data php occ ldap:show-config
from within your instance's installation folder

Without access to your command line download the data/owncloud.db to your local
computer or access your SQL server remotely and run the select query:
SELECT * FROM `oc_appconfig` WHERE `appid` = 'user_ldap';


Eventually replace sensitive data as the name/IP-address of your LDAP server or groups.

Client configuration

Browser: firefox 50.1.0

Operating system: windows 10

CalDAV-clients: nvt

Logs

Web server error log

Insert your webserver log here

Log file (data/owncloud.log)

Insert your ownCloud.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) ...