Nextcloud version (eg, 10.0.2): Nextcloud 11.0.2 (stable)
Operating system and version (eg, Ubuntu 16.04): Debian 8.7
Apache or nginx version (eg, Apache 2.4.25): Server version: Apache/2.4.10 (Debian)
PHP version (eg, 5.6): PHP 7.0.16-1~dotdeb+8.1
Is this the first time you’ve seen this error?: yes (first time using nextcloud as well had before owncloud and nope I deleted owncloud and then installed nextcloud)
Can you reliably replicate it? (If so, please outline steps):
The issue you are facing: memory info is not available
The output of your Nextcloud log in Admin > Logging: http://pastebin.com/GL8s04ti (most of them are errors because the mail app is not working (probably because Inbox Prefix is on from Froxlor standard configuration)
The output of your config.php file in /path/to/nextcloud
(make sure you remove any identifiable information!): http://pastebin.com/VJUiRyT5
The output of your Apache/nginx/system log in /var/log/____
: Dont know which log you need I have in /var/log/apache2 those logs access.log (dont think you need that) error.log and other_vhosts_access.log