Make sure the transmitter and receiver address are the same (at PIPE0)
RX_ADDR_P0-1 = 0xe7e7e7e7e7 0xe8e8f0f0e1
RX_ADDR_P2-5 = 0xc3 0xc4 0xc5 0xc6
TX_ADDR = 0xe7e7e7e7e7
RX_ADDR_P0-1 = 0xe8e8f0f0e1 0xc2c2c2c2c2
RX_ADDR_P2-5 = 0xc3 0xc4 0xc5 0xe1
TX_ADDR = 0xe8e8f0f0e1