Error in php SystemStatistics.php#74

Nextcloud version (eg, 13.0.1):
Operating system and version (eg, Archlinux x86):
Apache or nginx version (eg, Apache 2.4.29):
PHP version (eg, 7.2):

The issue you are facing:
Good afternoon, I tore nextcloud, later couple of days I began to view the log and noticed the following error. Search in ggogle didn’t yield results.

Is this the first time you’ve seen this error? (Y/N):Y

The output of your Nextcloud log in Admin > Logging:

is_readable(): open_basedir restriction in effect. File(/proc/meminfo) is not within the allowed path(s): (/srv/http/:/dev/urandom:/tmp/:/usr/share/pear/:/usr/share/webapps/nextcloud/:/etc/webapps/nextcloud) at /usr/share/webapps/nextcloud/apps/serverinfo/lib/SystemStatistics.php#74

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):

<?php
$CONFIG = array (
  'instanceid' => '********',
  'apps_paths' => 
  array (
    0 => 
    array (
      'path' => '/usr/share/webapps/nextcloud/apps',
      'url' => '/apps',
      'writable' => false,
    ),
    1 => 
    array (
      'path' => '/usr/share/webapps/nextcloud/apps2',
      'url' => '/apps2',
      'writable' => true,
    ),
  ),
  'datadirectory' => '/usr/share/webapps/nextcloud/data',
  'passwordsalt' => '*******',
  'secret' => '**********',
  'trusted_domains' => 
  array (
    0 => '********',
    1 => 'brothers.dynu.net',
  ),
  'overwrite.cli.url' => 'http://*******',
  'dbtype' => 'mysql',
  'version' => '13.0.1.1',
  'dbname' => 'nextcloud',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'dbuser' => 'nextcloud',
  'dbpassword' => '*********,
  'installed' => true,
  'memcache.local' => '\\OC\\Memcache\\APCu',
  'mail_smtpmode' => 'php',
  'mail_smtpauthtype' => 'LOGIN',
  'mail_from_address' => 'ilisei.el',
  'mail_domain' => 'gmail.com',
  'appstoreenabled' => true,
  'appstore.experimental.enabled' => true,
  'maintenance' => false,
  'loglevel' => 0,
  'session_lifetime' => 60 * 60 * 24,
  'auth.bruteforce.protection.enabled' => true,
  'enable_previews' => true,
);

Your php version, version of NC and the php configuration could be interesting. The error is quite obvious, did you try to put /proc/meminfo in the list of allowed paths for open_basedir()?

If you have security concerns regarding this settings, the error is probably created by the monitoring app.