Only allow register user to contact seller for perticular category

Hi,

can you point me to the code snippet you are using?

add_filter( "wp", "loggedin_members_only_init", 50 );
function loggedin_members_only_init() {
    if( is_singular( 'advert' ) && get_current_user_id() < 1 ) {
        remove_action( 'adverts_tpl_single_bottom', 'adverts_single_contact_information' );
        remove_action( 'adverts_tpl_single_bottom', 'adext_contact_form' );
        remove_action( 'adverts_tpl_single_bottom', 'adext_bp_send_private_message_button', 50 );

        add_action( 'adverts_tpl_single_bottom', "loggedin_members_only", 5 );
    }
}
function loggedin_members_only( $post_id ) {
    $flash = array( "error" => array(), "info" => array(), "warn" => array() );
    $flash["warn"][] = array(
        "message" => sprintf( "Only logged-in user can contact sellers. <a href=\"%s\">Login</a> or <a href=\"%s\">Register</a>", wp_login_url( get_permalink( get_the_ID() ) ), wp_registration_url() ),
        "icon" => "adverts-icon-block"
    );
    adverts_flash( $flash );
}

If you want this to run only when the category name/slug is for example cats or dogs then at the beginning of the loggedin_members_only_init function you can add the code below

    $run_only_in = [ "cats", "dogs" ];
    $do_run = false;
    if( ! is_singular( 'advert' ) ) {
      return;
    } 
    $terms = wp_get_post_terms( get_the_ID(), "advert_category" );
    $slugs = [];
    foreach( $terms as $term ) {
        $slugs[] = $term->slug;
    }
    foreach( $slugs as $slug ) {
        if( in_array( $slug, $run_only_in ) ) {
            $do_run = true;
        }
    }
    if( ! $do_run ) {
        return;
    }
    

On the first line you can list all the categories in which the whole code should be run.