Problem when converting DB

Nextcloud version (eg, 18.0.2): 17.0.3
Operating system and version (eg, Ubuntu 20.04):Raspbian GNU/Linux 10 (buster)
Apache or nginx version (eg, Apache 2.4.25): Apache 2.4.38
PHP version (eg, 7.1): 7.3.19

The issue you are facing:
I’m trying to convert my DB from SQLite to MySQL anda m having issues with it.

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

Steps to replicate it:

  1. follow Converting database type — Nextcloud latest Administration Manual latest documentation
  2. create new db all fine but when I execute the actual command I get the following output:
$ sudo -u www-data php occ db:convert-type --all-apps mysql root localhost nextcloud
What is the database password?

In Connection.php line 64:
                                                                                                                                        
  Failed to connect to the database: An exception occurred in driver: SQLSTATE[HY000] [1698] Access denied for user 'root'@'localhost'  

The output of your Nextcloud log in Admin > Logging:

No server logs

Everything is working fine

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

<?php
$CONFIG = array (
  'instanceid' => 'key',
  'passwordsalt' => 'key',
  'secret' => 'key',
  'trusted_domains' => 
  array (
    0 => 'raspi',
    1 => 'IP',
    2 => 'user.domain.org',
  ),
  'datadirectory' => '/var/nextcloud/data',
  'dbtype' => 'sqlite3',
  'version' => '17.0.3.1',
  'overwrite.cli.url' => 'http://raspi/nextcloud',
  'installed' => true,
  'maintenance' => false ,
  'theme' => '',
  'loglevel' => 0,
  'mail_from_address' => 'user',
  'mail_smtpmode' => 'smtp',
  'mail_sendmailmode' => 'smtp',
  'mail_domain' => 'mail.com',
  'mail_smtpauthtype' => 'LOGIN',
  'mail_smtpauth' => 1,
  'mail_smtphost' => 'smtp.mail.com',
  'mail_smtpport' => '465',
  'mail_smtpsecure' => 'ssl',
  'mail_smtpname' => 'user@mail.com',
  'mail_smtppassword' => 'pass',
  'filelocking.enabled' => true,
  'blacklisted_files' => array('.htaccess'),
  'onlyoffice' => 
  array (
    'verify_peer_off' => true,
  ),
  'app_install_overwrite' => 
  array (
    0 => 'twofactor_rcdevsopenotp',
  ),
);

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

...
192.168.1.1 - stdcerr [05/Jan/2021:23:23:23 +0000] "PROPFIND /nextcloud/remote.php/dav/files/stdcerr/USB/work/novax/src/novax-prs/docker/dey-2.2/sources/meta-openembedded/meta-oe/recipes-connectivity/modemmanager HTTP/1.1" 207 3047 "-" "Mozilla/5.0 (Linux) mirall/2.6.5-20200713.144448.adada8b2e-1.0~bionic1 (Nextcloud)"
192.168.1.1 - - [05/Jan/2021:23:23:32 +0000] "GET /nextcloud/ocs/v2.php/apps/notifications/api/v2/notifications HTTP/1.1" 200 1446 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:84.0) Gecko/20100101 Firefox/84.0"
192.168.1.222 - stdcerr [05/Jan/2021:23:23:13 +0000] "PUT /nextcloud/remote.php/dav/files/stdcerr/USB/work/novax/src/novax-prs/docker/dey-2.2/sources/meta-openembedded/meta-oe/recipes-support/mysql/mariadb/configure.cmake-fix-valgrind.patch HTTP/1.1" 201 743 "-" "Mozilla/5.0 (Linux) mirall/3.0.3git (Nextcloud)"
192.168.1.222 - stdcerr [05/Jan/2021:23:23:05 +0000] "PUT /nextcloud/remote.php/dav/files/stdcerr/USB/work/novax/src/novax-prs/docker/dey-2.2/sources/meta-openembedded/meta-oe/recipes-support/mysql/mariadb/change-cc-to-cc-version.patch HTTP/1.1" 201 743 "-" "Mozilla/5.0 (Linux) mirall/3.0.3git (Nextcloud)"

This while I can connect fine toi my db with $ sudo mysql -uroot from the shell