get_post_meta from user profile

Hi
i have setting some field for user profile
now i like to show the (example) Facebook Profile Url from Author’s post
i have try so
$text = get_post_meta( get_the_ID(), ‘cmb_user_facebookurl’, true );

and i have try so
$text = get_post_meta( $post->post_author, ‘cmb_user_facebookurl’, true );

without success

The question is how get the meta from user profile? Thx