LAMP+OC Error 500 without any logs

Please help us by providing the following info. Before posting please also check the pinned "Known issues" threads and make sure that you're running the latest available version for your oC release: https://owncloud.org/changelog/

Steps to reproduce
1. Install OC Server 10.0.0 (9.1.5, 9.1.4 the same)
2. Create proper configuration (Mysql, admin data, data directory on external disk)
3. Installation succesfull. However any owncloud page (including status.php) throws error 500

Expected behaviour
Normal web interface should show up / or desktop app should connect

Actual behaviour
Error 500 from Apache

Server configuration
Operating system: Raspbian
Web server: Apache2
Database: Mysql
PHP version: 5.6
ownCloud version (see ownCloud admin page): 10.0.0 (9.1.4 & 9.1.5 same beh.)
Updated from an older ownCloud or fresh install: Fresh install
Special configuration (external storage, external authentication, reverse proxy, server-side-encryption): External storage (on folder /mnt/axagon/cloud , folder has 0770 perms, www-data:www-data owners, every php process runs on www-data user). SSL encryption (SHA256) - HTTPS access only

ownCloud configuration

{
    "system": {
        "debug": true,
        "loglevel": 0,
        "instanceid": "ocaqemxn5jko",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "192.168.31.10",
            "cloud.klubpivovarek.cz"
        ],
        "datadirectory": "\/mnt\/axagon\/cloud",
        "overwrite.cli.url": "http:\/\/192.168.31.10\/owncloud",
        "dbtype": "mysql",
        "version": "10.0.0.12",
        "dbname": "owncloud",
        "dbhost": "localhost",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "logtimezone": "UTC",
        "installed": true,
        "maintenance": false
    }
}

ownCloud log (data/owncloud.log)
/mnt/axagon/cloud/owncloud.log - empty
/var/log/apache2/error.log:

[Wed May 03 06:25:12.121962 2017] [mpm_prefork:notice] [pid 1478] AH00163: Apache/2.4.10 (Raspbian) OpenSSL/1.0.1t configured -- resuming normal operations
[Wed May 03 06:25:12.122131 2017] [core:notice] [pid 1478] AH00094: Command line: '/usr/sbin/apache2'
[Wed May 03 14:39:26.245904 2017] [access_compat:error] [pid 6879] [client 66.249.93.18:46451] AH01797: client denied by server configuration: /var/www/tymy/
[Wed May 03 16:36:11.586728 2017] [mpm_prefork:notice] [pid 1478] AH00169: caught SIGTERM, shutting down
[Wed May 03 16:36:13.255697 2017] [mpm_prefork:notice] [pid 13729] AH00163: Apache/2.4.10 (Raspbian) OpenSSL/1.0.1t configured -- resuming normal operations
[Wed May 03 16:36:13.256026 2017] [core:notice] [pid 13729] AH00094: Command line: '/usr/sbin/apache2'

/var/log/apache2/access.log:

60.191.38.77 - - [03/May/2017:07:41:23 +0200] "GET /current_config/Account1 HTTP/1.1" 404 3711 "-" "Mozilla/5.0"
60.191.38.77 - - [03/May/2017:07:41:24 +0200] "GET /current_config/Account1 HTTP/1.1" 404 3711 "-" "Mozilla/5.0"
60.191.38.77 - - [03/May/2017:07:41:26 +0200] "GET /current_config/Account1 HTTP/1.1" 404 3711 "-" "Mozilla/5.0"
60.191.38.77 - - [03/May/2017:07:41:28 +0200] "GET /current_config/Account1 HTTP/1.1" 404 3711 "-" "Mozilla/5.0"
60.191.38.77 - - [03/May/2017:07:41:33 +0200] "GET /current_config/Account1 HTTP/1.1" 404 3711 "-" "Mozilla/5.0"
60.191.38.77 - - [03/May/2017:07:41:51 +0200] "GET /current_config/Account1 HTTP/1.1" 404 3711 "-" "Mozilla/5.0"
158.255.1.72 - - [03/May/2017:14:26:43 +0200] "GET / HTTP/1.1" 200 989 "-" "-"
66.249.93.18 - - [03/May/2017:14:39:26 +0200] "GET /tymy/ HTTP/1.1" 403 3765 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.75 Safari/537.36 Google Favicon"
139.162.78.135 - - [03/May/2017:15:50:00 +0200] "GET / HTTP/1.1" 200 3702 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.101 Safari/537.36"
185.110.132.239 - - [03/May/2017:16:12:20 +0200] "GET / HTTP/1.1" 200 952 "-" "Scanbot"
94.112.206.90 - - [03/May/2017:16:15:04 +0200] "GET /owncloud HTTP/1.1" 301 3859 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:04 +0200] "GET /owncloud/ HTTP/1.1" 503 8015 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/styles.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 9799 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/global.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1142 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/inputs.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 2787 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/fonts.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1069 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/apps.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 4211 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/header.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 2768 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/fixes.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 914 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/icons.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 2257 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/multiselect.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1579 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/mobile.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1747 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/jquery-ui-fixes.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1443 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/jquery.ocdialog.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1135 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/css/tooltip.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1344 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/jquery-migrate/jquery-migrate.min.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 4571 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/jquery-ui/themes/base/jquery-ui.css?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 6644 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/underscore/underscore.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 15547 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/jquery/dist/jquery.min.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 30331 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/blueimp-md5/js/md5.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 3473 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/bootstrap/js/tooltip.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 5047 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/es6-promise/dist/es6-promise.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 7459 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/backbone/backbone.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 20823 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/davclient.js/lib/client.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 3952 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/handlebars/handlebars.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 36376 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/moment/min/moment-with-locales.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 73771 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/bowser/src/bowser.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 4722 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/jquery.ocdialog.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 2555 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/clipboard/dist/clipboard.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 6056 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/oc-dialogs.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 7788 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/l10n.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 3142 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/octemplate.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 2062 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/eventsource.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 2345 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/oc-requesttoken.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 824 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/config.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1211 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/search/js/search.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 4078 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/apps.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1739 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/mimetype.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1978 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/mimetypelist.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1674 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/js.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 18457 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/placeholder.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 2626 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/jquery.avatar.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 2383 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/snapjs/dist/latest/snap.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 6578 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/oc-backbone.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 860 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/files/fileinfo.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1505 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/js/files/client.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 5664 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/core/vendor/jquery-ui/ui/jquery-ui.custom.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 107646 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:07 +0200] "GET /owncloud/index.php/core/js/oc.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 503 7735 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:08 +0200] "GET /owncloud/core/img/logo-icon.svg HTTP/1.1" 200 3443 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:08 +0200] "GET /owncloud/core/img/background.jpg HTTP/1.1" 200 134302 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:08 +0200] "GET /owncloud/core/fonts/OpenSans-Regular.woff HTTP/1.1" 200 21147 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:08 +0200] "GET /owncloud/core/fonts/OpenSans-Semibold.woff HTTP/1.1" 200 70579 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:15:08 +0200] "GET /owncloud/core/img/favicon.ico HTTP/1.1" 200 5503 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:21:01 +0200] "GET /owncloud/ HTTP/1.1" 503 10918 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:21:02 +0200] "GET /owncloud/index.php/core/js/oc.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 500 3583 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:22:00 +0200] "GET /owncloud/ HTTP/1.1" 503 7711 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:22:00 +0200] "GET /owncloud/index.php/core/js/oc.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 503 7711 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:22:01 +0200] "GET /owncloud/core/img/favicon.ico HTTP/1.1" 200 5641 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:22:24 +0200] "GET /owncloud/ HTTP/1.1" 503 7885 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:22:25 +0200] "GET /owncloud/core/js/maintenance-check.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 200 1092 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:22:25 +0200] "GET /owncloud/index.php/core/js/oc.js?v=18a6e9a979dab2a8c0b0913dfdc3010d HTTP/1.1" 500 537 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:22:55 +0200] "GET /owncloud/core/img/favicon.ico HTTP/1.1" 200 5641 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
114.85.103.14 - - [03/May/2017:16:23:06 +0200] "GET / HTTP/1.1" 200 989 "http://94.112.206.90/" "Mozilla/4.0 (compatible; MSIE 9.0; Windows NT 6.1)"
94.112.206.90 - - [03/May/2017:16:23:16 +0200] "GET /owncloud/status.php HTTP/1.1" 500 537 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:23:46 +0200] "GET /owncloud/status.php HTTP/1.1" 200 1106 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:23:55 +0200] "GET /owncloud/status.php HTTP/1.1" 500 537 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:24:25 +0200] "GET /owncloud/status.php HTTP/1.1" 500 537 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:24:55 +0200] "GET /owncloud/status.php HTTP/1.1" 200 1107 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:24:34 +0200] "GET /owncloud/ HTTP/1.1" 500 537 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:24:55 +0200] "GET /owncloud/status.php HTTP/1.1" 500 537 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:25:08 +0200] "GET /owncloud/ HTTP/1.1" 500 537 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:28:22 +0200] "GET /owncloud/ HTTP/1.1" 500 3583 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:31:42 +0200] "GET /owncloud/ HTTP/1.1" 500 537 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:34:03 +0200] "GET /owncloud/ HTTP/1.1" 500 3583 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:36:24 +0200] "GET /owncloud/ HTTP/1.1" 302 4007 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"
94.112.206.90 - - [03/May/2017:16:36:30 +0200] "GET /owncloud/index.php/login HTTP/1.1" 500 400 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"

Integrity status for oC9+

Login as admin user into your ownCloud and access
http://example.com/index.php/settings/integrity/failed
paste the results here.
 - Sorry, cannot paste it. Guess why :slight_smile:

Im not so sure if thats problem of apache2, php5 or owncloud. However another apps are working smoothly on my configuration, thats why i suspect OC is making some mess. Configuration of server is best to view in php info: https://cloud.klubpivovarek.cz/phpinfo.php .

Most strange thing is there is nothing where to look for errors.

What I tried?
Set error_log and display_log On, set different error log file in php.ini - no change
Set error_log and display_log On in /var/www/owncloud/.htaccess - no change
Set permissions of error log file to 0777 just to be sure - no change

Really bad error since you cannot do anything than just guess. If someone would be interested in some deep scanning I can maybe give you some slight SSH - server is basically empty right now