nRF24L01 Intermittent / No operation.[/size]
ALWAYS check 3.3V power. Many times intermittent operation is due to power supply regulation issues. Even though the average current may be less than 15ma, apparently there are quick transients when each transmit burst happens.
I used to have nRF24L01 problems. Worked one day / one minute, failed the next. Now I put a 1uf to 10uf capacitor right from GND to 3.3V pins on the modules, and things are MUCH better.
See the ArduinoInfo.Info WIKI HERE:
**These modules are designed to plug into a baseboard that usually has significant bypass capacitors. If you have them on the end of jumper wires you need extra bypass capacitors. **
Try it and let us know here!