I don't understand why.
{
    bool listen_try = config.getBool("listen_try", false);
    if (!listen_try)
        listen_try = DB::getMultipleValuesFromConfig(config, "", "listen_host").empty();
    return listen_try;
}
void Server::createServer(
    Poco::Util::AbstractConfiguration & config,
    const std::string & listen_host,
    const char * port_name,
    bool listen_try,
    bool start_server,
    std::vector<ProtocolServerAdapter> & servers,
    CreateServerFunc && func) const
{
    
    if (config.getString(port_name, "").empty())
        return;
    
    for (const auto & server : servers)
        if (!server.isStopping() && server.getListenHost() == listen_host && server.getPortName() == port_name)