wp_remote_get() not passing authentication

PHP Snippet 1:

$wp_request_headers = array(
    'Authorization' => 'Basic ' . base64_encode( 'username:password' )
);

$wp_request_url = 'http://localserver/wordpress-api/wp-json/wp/v2/posts/52';

$wp_delete_post_response = wp_remote_request(
    $wp_request_url,
    array(
        'method'    => 'DELETE',
        'headers'   => $wp_request_headers
    )
);

echo wp_remote_retrieve_response_code( $wp_delete_post_response ) . ' ' . wp_remote_retrieve_response_message( $wp_delete_post_response );