NRF24L01 1 master 2 slaves

I am working on NRF24L01 using 1 master and 2 slaves. I found the examples given in this tutorial: Simple nRF24L01 + 2.4GHz transceiver demo and am trying to use ackpayload method. I already tried the simple ackpayload example for 1 tx and 1 rx and it works for me but for some reason the 1 master 2 slaves example does not. I copied and paste the code given in the tutorial and only modified the CE and CSN pin to 8 and 9 because i already a have fixed circuit. I expected it to work because i don't change anything at all and only trying to study the code so i can use it for my project. Anyway it prints out "tx failed" repeatedly I am quite new to nrf24l01 I dont know what i am doing wrong. Hope anyone can help me with this. Thank you.

Output:

======== For Slave 0 ========
Data Sent ToSlv0 0 Tx failed

======== For Slave 1 ========
Data Sent ToSlv1 0 Tx failed
...
...
...

See OP's other nRF24 Thread

...R