Restore runcloud

Nextcloud version (18, 19, 20 and 21)
Operating system and version _(eg, Ubuntu 18.04
Apache or nginx version (eg, Apache 2.4):
PHP version (eg, 7,2, 7,3, 7.4, 8.0):

The issue you are facing:
I had php 7.2 working with nextcloud 18
I upgraded it to version 19 and it worked

I tried to change the php version and at the moment i have php 8 and nextcloud 21.

I run the occ upgrade 3 times to upgrade from 18, to 19, to 20 and to 21. The connection to nextcloud server is blocked on the server.

The command line worked to do the upgrade but i an bit able to see nextcloud paga and i got an error 500 error.

Changing on config the debug level i was able to overcome one memory limit error before.

Is it possible to have this instalation running or should i start from begining.
I have a dump of nextcloud database on version 18 and i may try to restore it aond do the steps at least to version 19 again.

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

Steps to replicate it:

The output of your Nextcloud log in Admin > Logging:

not able

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

$CONFIG = array (
  'instanceid' => 'ocdeascxhshb',
  'trusted_domains' => 
  'datadirectory' => '/var/www/nextcloud/data',
  'dbtype' => 'mysql',
  'version' => '21.0.2.1',
  'dbname' => 'nextcloud',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'dbuser' => 'nc_user',
  'dbpassword' => 
  'installed' => true,
  'memcache.locking' => '\\OC\\Memcache\\Redis',
  'memcache.distributed' => '\\OC\\Memcache\\Redis',
  'memcache.local' => '\\OC\\Memcache\\Redis',
  'redis' => 
  array (
    'host' => 'localhost',
    'port' => 6379,
    'timeout' => 3,
  ),
  'maintenance' => false,
  'loglevel' => 3,
);

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

PASTE HERE

Mon May 31 19:16:49.419341 2021] [proxy_fcgi:error] [pid 1669] [client 85.240.183.120:47022] AH01071: Got error ‘PHP message: PHP Fatal error: Uncaught OC\HintException: [0]: Memcache \OC\Memcache\Redis not available for local cache (Is the matching PHP module installed and enabled?)\n\n thrown in /var/www/nextcloud/lib/private/Memcache/Factory.php on line 98’
[Mon May 31 23:04:43.392209 2021] [proxy_fcgi:error] [pid 1669] [client 52.30.16.188:28723] AH01071: Got error ‘Primary script unknown’