keywords do not appear

Hi, keywords are not officially supported by Google News anymore.

They are still in the Advanced plugin but only on popular demand by our Pro users, not because they are proven to (still) be beneficial… They might be, but it’s not officially acknowledged by Google.

But there is still the xmlsf_news_keywords filter. You can use it like this, to add post_tag terms as keywords:

function my_custom_keywords( $keywords ) {
	global $post;

	$terms = get_the_terms( $post->ID, 'post_tag' );
	$names = array();

	if ( $terms && ! is_wp_error( $terms ) ) {
		foreach ( $terms as $term ) {
			if ( is_object($term) && !empty($term->name) )
				$names[] = $term->name;
		}
	}
	$keywords = array_merge( (array) $keywords, $names );

	return $keywords;
}
add_filter( 'xmlsf_news_keywords', 'my_custom_keywords' );