rf24Network library issue

Its probably a timing issue plus a bit of a coding issue. The main thing to remember is instead of delay(); calls you should keep the network updating and checking for incoming packets.

Something like:

  bool ok1 = network.multicast(header1, &data_req[0], data_req.length(), level1);
  uint32_t timer = millis();
  while( millis() - timer < 1000 ){ //Check for incoming packets for 1 second - adjust this as required
    network.update();
    //handle incoming packets here
  }