I used the snippet for custom post types (with the right slug), but that doesn’t change anything. The author names don’t stay in the drop down list, so that I can’t select them.
// Use CAP plugin with CPT ‘your_cpt_slug’.
add_filter( ‘coauthors_count_published_post_types’, function( $post_types ) {
$post_types[] = ‘tribe_events’;
return $post_types;
} );
add_post_type_support( ‘tribe_events’, ‘author’ );