# \[BLE\] Scan fails with "Scan Error" and "There is no scan" on Ameba Arduino D

**URL:** <https://forum.amebaiot.com/t/ble-scan-fails-with-scan-error-and-there-is-no-scan-on-ameba-arduino-d/4290>\
**Category:** BT\
**Tags:** rtl872xd\
**Created:** [July 30, 2025, 11:51am UTC](https://forum.amebaiot.com/t/ble-scan-fails-with-scan-error-and-there-is-no-scan-on-ameba-arduino-d/4290 "2025-07-30T11:51:40Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![sksrhkd](https://avatars.discourse-cdn.com/v4/letter/s/7c8e57/32.png) [@sksrhkd](https://forum.amebaiot.com/u/sksrhkd)\
**Post date:** [July 30, 2025, 11:51am UTC](https://forum.amebaiot.com/t/ble-scan-fails-with-scan-error-and-there-is-no-scan-on-ameba-arduino-d/4290/1 "2025-07-30T11:51:41Z")

</div>

Hello,

I am currently working on a project using the **Ameba Arduino D** environment, with the **AMB21/AMB22 (RTL8721DM)** board.

The application uses BLE to scan for nearby advertising devices and transmits the data to an external server.  
The following header files are being used:

```auto
#include "BLEDevice.h"
#include "BLEWifiConfigService.h"

```

The scanning logic is set to activate from second 0 to 30 of every minute. While it operates normally for a while, the following issue sometimes occurs:

1. `Scan Start` is logged,
2. Immediately followed by a `Scan Error`,
3. Then repeated messages saying `"There is no scan"` appear.

I would like to better understand the conditions under which this issue occurs, and would appreciate clarification on the following points:

1. Under what conditions are `"Scan Error"` and `"There is no scan"` messages triggered?

- Could this be due to internal BLE stack conflicts, resource limitations, or incorrect state transitions?

1. Are there any **recommended configurations or initialization steps to ensure stable BLE operation** in the Ameba Arduino D environment?

- For example: BLE stack initialization order, power settings, or scan interval constraints.

Also, once the issue occurs, BLE scanning does not resume until the board is manually reset.  
If there is a **way to deliberately reproduce the Scan Error** , it would greatly help with debugging and testing.

Any relevant documentation or suggestions you could provide would be sincerely appreciated.  
Thank you for your support.

**Additional Information:**

- When a “Scan Error” occurs, the reported `cause` value is `2`.  
I would appreciate any insight into what this specific cause value represents internally in the BLE stack.
- We are currently scanning and transmitting data from around **50 to 100 nearby devices** over HTTP.  
The issue typically occurs after **2 to 3 hours of continuous operation**.  
Any suggestions for long-term BLE stability would be highly appreciated.

Thank you very much for your support.