Basic Post Request isn't working

[ughstudios]

void RegisterUser(std::string username, std::string password)
{
    RestClient::init();
    std::unique_ptr<RestClient::Connection> conn = std::make_unique<RestClient::Connection>(GetRegistrationURL());
    conn->SetBasicAuth(username, password);
    conn->SetTimeout(5);
    conn->SetUserAgent("game");
    conn->AppendHeader("Content-Type", "application/json");
    nlohmann::json json_data;
    json_data["username"] = username;
    json_data["password"] = password;
    RestClient::Response resp = conn->post("", json_data.dump());
    RestClient::disable();
}

Why does this not send any http request? It compiles and runs without any errors or exceptions.