forward cant works

I try forward to another side request but it doesnt work?
Can everybody help me?
FilterProxy....
std::string public_ip = result[0]["public_ip"].as();

if(public_ip.empty())
return fccb();

// change protocol
std::regex pattern("(ws|wss|http|https)://");
public_ip = std::regex_replace(public_ip, pattern, "");
public_ip.insert(0, "https://"/*req->isOnSecureConnection() ? "https://" : "http://"*/);
req->attributes()->insert("public_ip", public_ip);

// forward to other parking by public IP
return drogon::app().forward(req, std::move(fcb), public_ip,10);
//return fccb();
}