Unknown function at 0xA60

[whoosh]

Hello,

I am new to the NRF52 SoC and BLE development. I've been using the ble_app_template and following along this tutorial to learn more about BLE development. I'm having a problem when attempting to connect using the NRF Connect mobile app to my NRF52 DK. The steps are as follows:

1. Run the compiled binary on the dev board through SEGGER. At this point, LED1 on the NRF52 DK is blinking.
2. Open the NRF Connect mobile app and locate the NORD device.
3. Connect to the NORD device on the mobile app

When I connect to the NORD device, LED1 NRF52 DK stops blinking and the mobile immediately brings me to a blank Client tab with the status "DISCONNECTED NOT BONDED". When I step through the program in Segger and get to this point in the execution, I obtain the error Unknown function 0xA60.

Does anyone have any insight as to what this means and how I can fix it?

Thanks in advance for any help.

[whoosh]

/**@brief Function for handling the Connect event.
 *
 * @param[in]   p_cus       Custom Service structure.
 * @param[in]   p_ble_evt   Event received from the BLE stack.
 */
static void on_connect(ble_cus_t * p_cus, ble_evt_t const * p_ble_evt)
{
    p_cus->conn_handle = p_ble_evt->evt.gap_evt.conn_handle;

    ble_cus_evt_t evt;

    printf("ble_cus.c on_connect entry\r\n");   
    evt.evt_type = BLE_CUS_EVT_CONNECTED;
    printf("ble_cus.c: Set event type to BLE_CUS_EVT_CONNECTED\r\n");
    p_cus->evt_handler(p_cus, &evt); //PROBLEM HERE
    printf("ble_cus.c on_connect exit\r\n");
}

I was able to narrow down the problem to the following line of code, (line 15) but still need help in understanding what 0xA60 means.