Upgrade 12.0.4.3 to 13.0.0 fails

Stuck in Upgrade loop from 12.0.4.3 to 13.0.0 with the following error

Update to 13.0.0

An error occurred.
Detailed logs
Preparing update
Set log level to debug
Turned on maintenance mode
Updating database schema

An error occurred.
Please reload the page.

Change to ‘maintenance’ => false, and install begins again with the same outcome

The output of your Nextcloud log in Admin > Logging:

Cannot login to access Admin > Logging

Next Cloud Info

Nextcloud version - 12.0.4.3
Linux sgp10.siteground.asia 3.12.18-clouder0
PHP version 7.1.14

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

<?php
$CONFIG = array (
  'instanceid' => 'occv9adk2rxx',
  'passwordsalt' => 'XWRGs4hFeYjbE0xHleq3DxQ3PVxuTa',
  'secret' => '6Ci5/7Non3LxPHCF+Ox0ffl/kp4CrNvb4+cEq+jX+BYiwUwM',
  'trusted_domains' => 
  array (
    0 => 'site.com',
    1 => 'www.site.com',
  ),
  'datadirectory' => '/home/site/ncdata',
  'overwrite.cli.url' => 'https://site.com/nextcloud',
  'dbtype' => 'mysql',
  'version' => '12.0.4.3',
  'dbname' => 'site_nextcloud',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'dbuser' => 'xxxxxxx',
  'dbpassword' => 'xxxxxxxx',
  'logtimezone' => 'UTC',
  'installed' => true,
  'updater.server.url' => 'https://updates.nextcloud.com/updater_server/',
  'updater.release.channel' => 'stable',
  'maintenance' => true,
  'filelocking.enabled' => false,
  'theme' => '',
  'loglevel' => 2,
  'trashbin_retention_obligation' => 'auto',
  'updater.secret' => 'xxxxxxx',
);

The output of your Apache/nginx/system log in /var/log/____:

110.209.20.107 - - [12/Feb/2018:20:04:00 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:04:29 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:04:31 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:04:59 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:05:00 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:05:29 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:05:31 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:05:59 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:06:01 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:06:30 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:06:31 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:06:59 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:07:01 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:07:29 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:07:30 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:07:59 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:08:00 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:08:29 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:08:31 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:08:59 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:09:00 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:09:29 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:09:31 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:09:59 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:10:00 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:10:29 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:10:31 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:10:59 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:11:01 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:11:29 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:11:31 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:11:59 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:12:01 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:12:29 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:12:30 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:12:59 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:13:01 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:13:29 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:13:31 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:13:59 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:14:01 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:14:29 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:14:30 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:14:59 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"
110.209.20.107 - - [12/Feb/2018:20:15:00 +0800] "PROPFIND /nextcloud/remote.php/dav/files/yerg55/ HTTP/1.0" 207 504 "-" "Mozilla/5.0 (Macintosh) mirall/2.3.3 (build 84) (Nextcloud)"