> For the complete documentation index, see [llms.txt](https://docs.efento.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.efento.io/nb-iot-loggers/integrations/efento-coap-loader/troubleshooting.md).

# Troubleshooting

This section addresses common integration issues and explains how to interpret the status information from the Efento mobile application.

#### Server does not receive data from the sensor

If your platform is not receiving any requests, first verify the sensor’s cellular connection using the Efento mobile app (Android). Connect to the sensor and open the **Cellular Status** screen.

Check the following parameters:

* **Registration status** – must be *REGISTERED*
* **ECL** – should have a value (e.g., LEVEL\_0, LEVEL\_1, LEVEL\_2)
* **Cell ID** – must contain a valid value

If the sensor is registered but no data is received, the issue is likely on the integration side. Please verify:

* Server IP address configuration
* Server port and firewall settings
* APN settings (confirm with your mobile network operator)

***

#### Sensor is registered but sends the same data (retransmissions)

This issue occurs when your application returns an incorrect HTTP status code. The sensor treats any response outside the 2xx range as a failure and continues retransmitting the same data. In the **Cellular Status** screen, this is indicated as *MISMATCH* in the Communication status.

Another possible cause is a slow server response. If the response does not reach the sensor before it enters power-saving mode, the device assumes the transmission failed and retries sending the data.

**Solution:** Ensure your server responds with **201 Created** (or another 2xx status code), and that the response is returned quickly enough to reach the device before it enters power-saving mode.\
**Test:** Use a tool like Postman to send a sample JSON request to your endpoint and verify that the response status is **201 Created**.

***

#### Sensor is registered but data is not received

This usually means the sensor successfully connected to the network, but the request to your platform timed out or was blocked. In the **Cellular Status** screen, this appears as *TIMEOUT* in the Communication status.

**Possible causes:** Connectivity issues or incorrect APN settings.\
**What to check:** Verify that the APN is configured according to your connectivity provider’s requirements. If needed, contact your operator to identify the issue.

***

#### Still having issues?

If the sensor is registered but communication still fails despite correct response codes, please open a support ticket at **help.efento.io**.

{% hint style="info" %}
To speed up troubleshooting, include all details from the **Cellular Status** screen in the mobile app.
{% endhint %}


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