Support intro
Sorry to hear you’re facing problems 
help.nextcloud.com is for home/non-enterprise users. If you’re running a business, paid support can be accessed via portal.nextcloud.com where we can ensure your business keeps running smoothly.
In order to help you as quickly as possible, before clicking Create Topic please provide as much of the below as you can. Feel free to use a pastebin service for logs, otherwise either indent short log examples with four spaces:
example
Or for longer, use three backticks above and below the code snippet:
longer
example
here
Some or all of the below information will be requested if it isn’t supplied; for fastest response please provide as much as you can 
Nextcloud version (eg, 12.0.2): 13.0.4
Operating system and version (eg, Ubuntu 17.04): FreeBSD 11
Apache or nginx version (eg, Apache 2.4.25): nginx/1.12.0
PHP version (eg, 7.1): PHP 7.0.19
The issue you are facing:
Debug notices.
Is this the first time you’ve seen this error? (Y/N): N
Steps to replicate it:
The output of your Nextcloud log in Admin > Logging:
Debug OC\Files\Cache\Scanner !!! Path '' is not accessible or present !!!
Debug core OC\Tags::getFavorites, exception: Could not find category "_$!<Favorite>!$_"
The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):
'memcache.local' => '\\OC\\Memcache\\APCu',
'memcached_servers' =>
array (
0 =>
array (
0 => 'localhost',
1 => 11211,
),
),
'memcache.locking' => '\\OC\\Memcache\\Redis',
'redis' =>
array (
'host' => '/var/run/redis/redis.sock',
'port' => 0,
),
'maintenance' => false,
The output of your Apache/nginx/system log in /var/log/____:
2018/07/23 11:22:06 [info] 38359#101906: *6938 client canceled stream 819 while sending request to upstream, client: 192.168.1.1, server: files.domain.com, request: "GET /apps/logreader/poll?lastReqId=QVBfFF42iNvGhOkUGGd HTTP/2.0", upstream: "fastcgi://unix:/var/run/php-fpm.sock:", host: "files.domain.com"
2018/07/23 11:22:25 [info] 38359#101906: *7194 kevent() reported that client 255.255.110.247 closed idle connection
2018/07/23 11:22:27 [warn] 38359#101906: *7197 an upstream response is buffered to a temporary file /var/tmp/nginx/fastcgi_temp/7/01/0000000017 while reading upstream, client: 255.255.110.247, server: files.domain.com, request: "PROPFIND /remote.php/webdav/Photos/2018/03 HTTP/2.0", upstream: "fastcgi://unix:/var/run/php-fpm.sock:", host: "files.domain.com"
2018/07/23 11:22:27 [warn] 38359#101906: *7197 an upstream response is buffered to a temporary file /var/tmp/nginx/fastcgi_temp/8/01/0000000018 while reading upstream, client: 255.255.110.247, server: files.domain.com, request: "PROPFIND /remote.php/webdav/Photos/2018/04 HTTP/2.0", upstream: "fastcgi://unix:/var/run/php-fpm.sock:", host: "files.domain.com"
I see these two messages repeating. I think the cache one is new. Don’t recall seeing before updating nc to latest.
Debug OC\Files\Cache\Scanner !!! Path ‘’ is not accessible or present !!!
Debug core OC\Tags::getFavorites, exception: Could not find category “$!!$”
Not sure if related… but in phone app, there’s a download under transfers that shows “error code 28” which I have no idea what that means.