Why nRf51822 is not connecting to my mobile having 4.0 bluetooth ? BUT only connect when i use Official app

[Muhammad Fahad Aziz]

My phone : Lenovo Phab

Problem : cannot pair with nRf 51822 from Bluetooth menu BUT when i use Official App ( NRF Utility etc) then connect and start receiving data "

Notification on pairing request : incorrect pass key ( it didnt prompt for a passkey but when i click to pair just says Incorrect key) ??

am i missing something plzz Help

[Petter Myhre]

What application are you running on the nRF51?

[Roger Clark]

I think the OP is confusing conventional Bluetooth with Bluetooth low energy