This is a generic issue with Joomla and quick start packages. You will need to edit your database with phpmyadmin.
Below is the steps. Please backup your database before making changes. Change "Jos" with your prefix as it might be different.
1. Open your Joomla database using PHPMyadmin tool.
2. Open "jos_users" table,
3. Find record with "Super User" name and click on edit icon,
4. Change Super User id value to 42 and click on "Go" button,
5. Open "jos_user_usergroup_map" table.
6. Find the record with "group_id" value 8, change "user_id" value to 42, then click on "Go" button,
7. Logout and login again.
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Result !
Database connection error (2): Could not connect to MySQL.
I changed the values back (MySQL) and ... I can not connect with the site. MySQL error.