Internal server error after stretch>buster

Hi folks,

Nextcloud version (eg, 20.0.5): 20.0.8.1
Operating system and version : NextcloudPi Raspbian GNU/Linux 9
Apache or nginx version (eg, Apache 2.4.25): 2.4.something
PHP version (eg, 7.4):

The issue you are facing:

I had my nextcloudpi running smoothly for abour 2 years, now I get Internal server error and in the log file, I got this:

“Failed to connect to the database: An exception occurred in driver: SQLSTATE[HY000] [2002] No such file or directory”

The error occured out of the blue, I guess right after updating to v20

upgraded from stretch to buster, upgraded PHP 7.1 to 7.3

when I run nc-info from ncp-config, it says: … Nextcloud check: error …

All files stored on a synology station, which is properly mounted and accessible

I’m at my wits end, any help would be greatly appreciated!

Is this the first time you’ve seen this error?: Yes

Steps to replicate it:

Try to open nextcloud via webinterface

The output of your Nextcloud log in Admin > Logging:

huh?

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

$CONFIG = array (
  'passwordsalt' => '<rm>',
  'secret' => '<rm>',
  'trusted_domains' =>
  array (
    0 => 'localhost',
    5 => 'nextcloudpi.local',
    7 => 'nextcloudpi',
    8 => 'nextcloudpi.lan',
    1 => '192.168.178.90',
    11 => '2003:ca:bf23:c100:abb4:74ef:1b5d:a4ec',
    20 => '192.168.178.1',
    21 => '<rm>.duckdns.org',
    22 => '192.168.1.15',
    2 => '<blank>',
    4 => '<blank>.duckdns.org',
  ),
  'datadirectory' => '/media/USBdrive/ncdata',
  'dbtype' => 'mysql',
  'version' => '20.0.8.1',
  'overwrite.cli.url' => 'https://<rm>.duckdns.org/',
  'dbname' => 'nextcloud',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'mysql.utf8mb4' => true,
  'dbuser' => 'ncadmin',
  'dbpassword' => '<rm>',
  'installed' => true,
  'instanceid' => 'ockhnd03zkvv',
  'memcache.local' => '\\OC\\Memcache\\Redis',
  'memcache.locking' => '\\OC\\Memcache\\Redis',
  'redis' =>
  array (

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

which one?

Fixed it by setting up apache2 anew and upgrading stretch → Buster

[topic can be closed now]