Set the espresso_events post type show_in_rest arg to true.

tw_ee_set_show_in_rest_on_espresso_events.php

<?php // Please do not include the opening PHP tag if you already have one.

function tw_ee_set_show_in_rest_on_espresso_events( $args, $post_type ) {
    if ( 'espresso_events' === $post_type ) {
        $args['show_in_rest'] = true;
    }
    return $args;
}
add_filter( 'register_post_type_args', 'tw_ee_set_show_in_rest_on_espresso_events', 10, 2 );