Unable to select the specified database

You can verify if CodeIgniter is able to establish a connection with the database by creating a simple test script. Create a new PHP file, for example, `test_db.php`, in the root folder of your CodeIgniter project. Add the following code to the file:

```php
<?php
$connection = mysqli_connect('localhost', 'your_username', 'your_password', 'archives_collection');
if (!$connection) {
die('Database connection failed: ' . mysqli_connect_error());
} else {
echo 'Database connection successful!';
}
?>
```