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Sorry to hear you’re facing problems 
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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:
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, 20.0.5): 20.0.14.2
Operating system and version (eg, Ubuntu 20.04): centos 8 stream
Apache or nginx version (eg, Apache 2.4.25): 2.4.45
PHP version (eg, 7.4): 7.2
The issue you are facing:
Is this the first time you’ve seen this error? (Y/N): Y
Steps to replicate it:
open web page
I moved my nextcloud 20 to a new server centos 8 so I can upgrade it to latest version.
But now I get white blank page when I enable deebug in php.ini I get this errors
The output of your Nextcloud log in Admin > Logging:
The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):
<?php
$CONFIG = array (
'trusted_domains' =>
array (
0 => 'nextcloud.cccc.net',
),
'datadirectory' => '/data/nextcloud',
'tempdirectory' => '/var/www/html/nextcloud/tmp',
'overwrite.cli.url' => 'http://nextcloud.cccc.net',
'dbtype' => 'mysql',
'version' => '20.0.14.2',
'dbname' => 'nextcloud',
'dbhost' => 'localhost',
'dbport' => '',
'dbtableprefix' => 'oc_',
'dbuser' => 'nextcloud',
'dbpassword' => 'xxxx',
'installed' => true,
'debug' => false,
'force_language' => 'sl',
'knowledgebaseenabled' => true,
'mail_from_address' => 'dennis',
'mail_smtpmode' => 'smtp',
'mail_domain' => 'mail.cccc.net',
'maintenance' => false,
'trashbin_retention_obligation' => 'auto',
'logtimezone' => 'UTC',
'theme' => '',
'loglevel' => 2,
'preview_max_x' => 800,
'preview_max_y' => 800,
'preview_max_scale_factor' => 1,
'mail_smtphost' => 'localhost',
'mail_smtpport' => '25',
'mysql.utf8mb4' => true,
'has_rebuilt_cache' => true,
‘debug’ => true,
'app_install_overwrite' =>
array (
0 => 'admin_notifications',
1 => 'files_reader',
),
'encryption.legacy_format_support' => false,
'encryption.key_storage_migrated' => false,
);
The output of your Apache/nginx/system log in /var/log/____:
no errors
Warning: require_once(/var/www/html/nextcloud/lib/versioncheck.php): failed to open stream: No such file or directory in /var/www/html/nextcloud/index.php on line 32
Fatal error: require_once(): Failed opening required ‘/var/www/html/nextcloud/lib/versioncheck.php’ (include_path=’.:/usr/share/pear:/usr/share/php’) in /var/www/html/nextcloud/index.php on line 32
Output errors in nextcloud.log in /var/www/ or as admin user in top right menu, filtering for errors. Use a pastebin service if necessary.
PASTE HERE