By default, PHPMyAdmin requires a password other than a blank password. To remedy this, edit config.inc.php as shown below.
/* Authentication type */
//$cfg['Servers'][$i]['auth_type'] = 'cookie';
$cfg['Servers'][$i]['auth_type'] = 'config';
$cfg['Servers'][$i]['username'] = 'root';
$cfg['Servers'][$i]['password'] = '';
Make sure you seet the password in mysql.ini to nothing if you have it set to something.
[client]
password=
You will also need to make sure that the MySQL/MariaDB root user is set to use no password.
If you have a database password set in your apps, you will need to set them to a blank password.
That is all.