BLE_APP_TEMPLATE connection ecryption error in SDK 15.1

[Ars Morozov]

Hello. I've migrated my application from SDK 14.2 to 15.1 and I obtain this strange message from peer_manager_handler in my log: 

<info> peer_manager_handler: Connection security failed: role: Peripheral, conn_handle: 0x0, procedure: Encryption, error: 4102

I obtain this message only when I connect with nRF_Connect app on Iphone. When I connect with Android everything is fine.


My application is based on ble_app_template. So, I upload clean ble_app_template from SDK 15.1 and still obtain this message. When I check it on ble_app_template from SDK 14.2, message is disapear.

What does this message mean? And have can I deal with it?

[Peter B]

I have the same error message running the Heart Rate Sensor example "ble_app_hrs" on the nRF52840 using the nRF5_SDK_15.2.0_9412b96. As a newbie I was playing with the YouTube tutorial from Nordic regarding debugging in Segger Embedded Studio.

It occurs if I a connect the the nRF52840 using my iPhone (iOS 12.0.1) with a BLE app like nRF Connect or BLE Scanner:

peer_manager_handler: Connection security failed: role: Peripheral, conn_handle: 0x0, procedure: Encryption, error: 4102
app: GATT ATT MTU on connection 0x0 changed to 185.

But I get no errors with the same 2 apps on Android smartphone when I connect, also the MTU value is different then with the iPhone.

Connected.
app: GATT ATT MTU on connection 0x0 changed to 247.