How to disable peer manage in ble_app_buttonless_dfu project in sdk15.3.0 nrf52810?

Hi,I have some problems when disable peer manage in ble_app_buttonless_dfu project in sdk15.3.0 on nrf52810.

I disable PEER_MANAGER_ENABLED in config.h and remove the peer manage module relevant code in main.c.

In config.h

// <e> PEER_MANAGER_ENABLED - peer_manager - Peer Manager
//==========================================================
#ifndef PEER_MANAGER_ENABLED
#define PEER_MANAGER_ENABLED 0//1 //For_code_size_optimization//DEBUG_BY_LUOGF
#endif

In main.c

#if 1 //For_code_size_optimization
#else
/**@brief Function for handling Peer Manager events.
 *
 * @param[in] p_evt  Peer Manager event.
 */
static void pm_evt_handler(pm_evt_t const * p_evt)
{
    pm_handler_on_pm_evt(p_evt);
    pm_handler_flash_clean(p_evt);
}
#endif

#if 1 //For_code_size_optimization
#else
/**@brief Function for the Peer Manager initialization.
 */
static void peer_manager_init()
{
    ble_gap_sec_params_t sec_param;
    ret_code_t           err_code;

    err_code = pm_init();
    APP_ERROR_CHECK(err_code);

    memset(&sec_param, 0, sizeof(ble_gap_sec_params_t));

    // Security parameters to be used for all security procedures.
    sec_param.bond           = SEC_PARAM_BOND;
    sec_param.mitm           = SEC_PARAM_MITM;
    sec_param.lesc           = SEC_PARAM_LESC;
    sec_param.keypress       = SEC_PARAM_KEYPRESS;
    sec_param.io_caps        = SEC_PARAM_IO_CAPABILITIES;
    sec_param.oob            = SEC_PARAM_OOB;
    sec_param.min_key_size   = SEC_PARAM_MIN_KEY_SIZE;
    sec_param.max_key_size   = SEC_PARAM_MAX_KEY_SIZE;
    sec_param.kdist_own.enc  = 1;
    sec_param.kdist_own.id   = 1;
    sec_param.kdist_peer.enc = 1;
    sec_param.kdist_peer.id  = 1;

    err_code = pm_sec_params_set(&sec_param);
    APP_ERROR_CHECK(err_code);

    err_code = pm_register(pm_evt_handler);
    APP_ERROR_CHECK(err_code);
}


/** @brief Clear bonding information from persistent storage.
 */
static void delete_bonds(void)
{
    ret_code_t err_code;

    NRF_LOG_INFO("Erase bonds!");

    err_code = pm_peers_delete();
    APP_ERROR_CHECK(err_code);
}
#endif

/**@brief Function for application main entry.
 */
int main(void)
{
    bool       erase_bonds;
    ret_code_t err_code;

    log_init();

    #if 0
    // Initialize the async SVCI interface to bootloader before any interrupts are enabled.
    err_code = ble_dfu_buttonless_async_svci_init();
    APP_ERROR_CHECK(err_code);
    #endif

    timers_init();
    power_management_init();
    buttons_leds_init(&erase_bonds);
    ble_stack_init();
    #if 1 //For_code_size_optimization
    #else
    peer_manager_init();
    #endif
    gap_params_init();
    gatt_init();
    advertising_init();
    services_init();
    conn_params_init();

    NRF_LOG_INFO("Buttonless DFU Application started.");

    // Start execution.
    application_timers_start();
    advertising_start(erase_bonds);

    // Enter main loop.
    for (;;)
    {
        idle_state_handle();
    }
}

The device advertise well, but can not be connected by application.

I wonder if I miss something useful.ThanKs.