nRF52840 not advertising after disconnect

[akaun]

I'm developing a product using an nRF52840 and an accelerometer. 

I have created a Service with characteristic that sends accelerometer data over ble to the phone through notification. I have a problem that I do not know how to solve with disconnecting from device, when I disconnect the advertisement does not restart. The light is not blinking and the log not showing "advertising fast".

Current behavior only happens after I request notification from the phone. Lets say if i just connect and disconnect everything is fine, but if i connect, enable notification, then disable and disconnect, device doesn't restart advertising. It says "Disconnected" but that's it. In my service on notification callback i turn on accelerometer interrupt, and then send data, or start app_timer and send the data that way. Interestingly if i comment out enable interrupt or app_timer_start, everything seems to be ok.

The app is based on Template App.

Any idea what can be stopping the app from advertising?? Much help would be appreciated.

static void on_imus_evt(ble_imus_t * imus, ble_imus_evt_t * p_evt)
{
    switch (p_evt->evt_type)
    {
        case BLE_IMUS_EVT_NOTIFICATION_ENABLED:
            NRF_LOG_INFO("IMUS EVNT: NOTIF ENABLED");
            //icm42_enable_interrupt(&sensor_icm42);
            app_timer_start(measurement_timer, APP_TIMER_TICKS(100), NULL);
            break;
    
        case BLE_IMUS_EVT_NOTIFICATION_DISABLED:
            NRF_LOG_INFO("IMUS EVNT: NOTIF DISABLED");
            //icm42_disable_interrupt(&sensor_icm42);
            app_timer_stop(measurement_timer);
            break;
    
        default:
            // No implementation needed.
            break;
    }
}

  

[akaun]

It looks like GATT_Server_Timeout why the error happens.

case BLE_GATTS_EVT_TIMEOUT:
            // Disconnect on GATT Server timeout event.
            NRF_LOG_DEBUG("GATT Server Timeout.");
            err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            APP_ERROR_CHECK(err_code);
            break;

[Kenneth]

You are executing an sd_ble_gatts_*() procedure at some time, and there is no response from the peer, causing an:
https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s140.api.v7.0.1/group___b_l_e___g_a_t_t_s___t_i_m_e_o_u_t___m_s_c.html

If you are able to find which sd_ble_gatts_*() that is called and not responded that would help. Maybe an on-air sniffer log can be done.