Email Notifications not working

I am refering to this topic in the old forum: https://forum.owncloud.org/viewtopic.php?p=120301

As a recap of what has been done and said:

Steps to reproduce
1. Personal settings -> Activity: Tick every Mail-Notification-Checkbox
2. Create/Delete/Change files and folders

Expected behaviour
Receiving an email with changes done to the files and folders

Actual behaviour
Receiving no email

Server configuration
Operating system: Ubuntu 16.04 LTS (GNU/Linux 4.4.0-22-generic x86_64)
Web server: Apache/2.4.18 (Ubuntu) - 2.4.18-2ubuntu3.1
Database: MariaDB 10.0.25-0ubuntu0.16.04.1
PHP version: PHP 7.0.4-7ubuntu2.1
ownCloud version (see ownCloud admin page): ownCloud 9.0.3 (stable)
Updated from an older ownCloud or fresh install: 9.0 fresh install, 9.0.1 and 9.0.3 updated
ownCloud log (data/owncloud.log): pastebin.com/raw/BNhuu5Em

Special configuration (external storage, external authentication, reverse proxy, server-side-encryption):
Separate hard drive mounted in /.../data, ownCloud Test email working

Possible cause:
{"reqId":"w7iRpVG1Y6XyQYs6rogn","remoteAddr":"1.2.3.1","app":"sharing","message":"Can't send mail to inform the user about an internal share: Address in mailbox given [@] does not comply with RFC 2822, 3.6.2.","level":3,"time":"2016-06-07T18:31:48+02:00","method":"POST","url":"\/core\/ajax\/share.php","user":"comp"}

We did set a valid (and existing) address in the form of a.user@domain.com for the user and did verify the mail settings by sending a test mail which we received within seconds.

Perhaps the log excerpt with the error message I posted is unrelated after all. We updated to 9.0.3 a couple of days ago, tested it, haven't received a notification email and nothing shows up in the logs.

After setting the logging level to debug and testing it again, the log doesn't look like it's sending any email at all: http://pastebin.com/raw/8JgVGbPX

The mail server log shows the test mail we sent but nothing more. No mails were blocked.

We appreciate any help or ideas to solve the problem. Thanks in advance!

Hi,

it seems thats a starting point for debugging. When having a look at:

it seems that there should be the full e-mail (e.g. [foo@bar] in the error message where your error just contains the [@]

{"reqId":"cOGGc\/sXnrhascKkzDTj","remoteAddr":"","app":"OC\\Files\\Cache\\Scanner","message":"!!! Path '' is not accessible or present !!!","level":0,"time":"2016-07-21T08:45:01+02:00","method":"--","url":"--","user":"--"}

This doesn't look right and could be related to your problem.

@RealRancor: It looks like it might be related indeed. However, we haven't received that error ever since and the email address didn't contain any whitespaces or special characters I'm afraid.

@tflidd: What kind of confuses me is the empty path it shows in the log entry. After every installation and update we made sure to run the script for setting the correct permissions. (https://doc.owncloud.org/server/9.0/admin_manual/installation/installation_wizard.html#strong-perms-label), thus I'm wondering that file it can't access or find. Is there any form of further debugging apart from going into code level in order to find out?

What apps are you using? Perhaps you can deactivate some and try again.

How do you send mails, sendmail, php or smtp? smtp didn't always work well, you could try php and then install ssmtp (small mail daemon) to pass mails to your mailserver.

Or open a bug report?

@tflidd: We are using the standard apps: Activity, Collaborative tags, Comments, Deleted files, Federation, First Run Wizard, Gallery, Mail Template Editor, Notifications, PDF Viewer, Provisioning API, Share Files, Text Editor, Update notification, Versions, Video Player. We didn't install anything.

We were using SMTP. After trying out PHP and ssmtp, the email test again was working, but we received no notifications.