Varnish configuration file - Not working

varnish.vcl

backend default {
    .host = "127.0.0.1";
    .port = "80";
}

sub vcl_recv {
    set req.http.Surrogate-Capability = "abc=ESI/1.0";
}

sub vcl_fetch {
    if (beresp.http.Surrogate-Control ~ "ESI/1.0") {
        unset beresp.http.Surrogate-Control;
        set beresp.do_esi = true;
    }

    if (beresp.http.Cache-Control ~ "s-maxage") {
        unset req.http.Cookie;
        return (deliver);
    }

    return (hit_for_pass);
}