two NRF51822 communication fails sometimes

[phob]

Hi, I am using 2 nrf51822 devices. one is central and other one is peripheral. I am using s130 softdevice. When i was trying to connect NRF51822 to other nrf51822. i tried for 1st time then communication happens. But later communication happens once in 10 time.

But when i was trying to connec NRF51822 with NRF52 DK board NRF51822 was central and NRF52 DK was peripheral. That time communihcation was happening everytime.

What could be the problem.

[phob]

I am using SDK v12.2.0. I think in the case i mentioned, Central device(NRF51822) is working fine. But when i use second NRF51822 for peripheral then communication is not happening. Not getting connect to central. But When i use NRF52 as peripheral with same code then It works. But i have to use NRF51822 only. Communication fails means they are not at all getting connect. not pairing as well. I have don't have sniffer to capture the log.