Unable to disable pairing in my peripheral app

mul 9 hours ago

I have a simple GATT server application with two characteristics, RX and TX. In my prj.conf, I am trying to disable pairing as follows :

CONFIG_BT_BONDABLE=n
CONFIG_BT_SMP=n

I can connect to the server from a BLE scanner app. When I try to write to the TX characteristic, it asks me for a pairing code, and then disconnects if I don't have it. How to solve this? Thanks in advance. This is how I enable BLE and start advertising :

    ret = bt_enable(NULL);
	if (ret) {
		return ret;
	}


    bt_gatt_cb_register(&gatt_callbacks);
    bt_conn_cb_register(&conn_callbacks);

    if (IS_ENABLED(CONFIG_SETTINGS)) {
		settings_load();
	}

    /* Start advertising */
    ret = bt_le_adv_start(BT_LE_ADV_CONN_ONE_TIME, NULL, 0, NULL, 0);
    if (ret) {
        return ret;
    }