Error 14 (0xe): GATT ERR UNLIKELY

[IvanR]

After sending a notification that is less than the negotiated MTU. It is less than 20 bytes

It occurs sporadically. 

I 10:26:08.450 Notification received from 15ff1845-05d3-4c5b-8281-93d4e07420cf, value: (0x) 30-2E-30-30-2C-2D-30-2E-30-30-2C-30-2E-30-32, "0.00,-0.00,0.02"
A 10:26:08.450 "(0x) 30-2E-30-30-2C-2D-30-2E-30-30-2C-30-2E-30-32, "0.00,-0.00,0.02"" received
I 10:26:08.453 Notification received from 15ff1845-05d3-4c5b-8281-93d4e07420cf, value: (0x) 30-2E-30-31-2C-2D-30-2E-30-30-2C-30-2E-30-34, "0.01,-0.00,0.04"
A 10:26:08.453 "(0x) 30-2E-30-31-2C-2D-30-2E-30-30-2C-30-2E-30-34, "0.01,-0.00,0.04"" received
I 10:26:08.457 Notification received from 15ff1845-05d3-4c5b-8281-93d4e07420cf, value: (0x) 30-2E-30-30-2C-2D-30-2E-30-30-2C-30-2E-30-33, "0.00,-0.00,0.03"
A 10:26:08.457 "(0x) 30-2E-30-30-2C-2D-30-2E-30-30-2C-30-2E-30-33, "0.00,-0.00,0.03"" received
E 10:26:08.458 Error 14 (0xe): GATT ERR UNLIKELY

I use nRF Connect app for testing on Android.

[IvanR]

Wireshark and nrf52840 dongle don't see those packets. 

[IvanR]

Frame 3478: 35 bytes on wire (280 bits), 35 bytes captured (280 bits) on interface COM36-4.2, id 0
    Section number: 1
    Interface id: 0 (COM36-4.2)
        Interface name: COM36-4.2
        Interface description: nRF Sniffer for Bluetooth LE COM36
    Encapsulation type: nRF Sniffer for Bluetooth LE (186)
    Arrival Time: Nov 23, 2023 12:07:47.818196000 Central European Standard Time
    UTC Arrival Time: Nov 23, 2023 11:07:47.818196000 UTC
    Epoch Arrival Time: 1700737667.818196000
    [Time shift for this packet: 0.000000000 seconds]
    [Time delta from previous captured frame: 0.000230000 seconds]
    [Time delta from previous displayed frame: 0.011480000 seconds]
    [Time since reference or first frame: 24.821341000 seconds]
    Frame Number: 3478
    Frame Length: 35 bytes (280 bits)
    Capture Length: 35 bytes (280 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: nordic_ble:btle:btl2cap:btatt]
nRF Sniffer for Bluetooth LE
    Board: 36
    Header Version: 3, Packet counter: 47146
        Length of payload: 28
        Protocol version: 3
        Packet counter: 47146
        Packet ID: 6
    Length of packet: 10
    Flags: 0x01
        .... ...1 = CRC: Ok
        .... ..0. = Direction: Slave -> Master
        .... .0.. = Encrypted: No
        .... 0... = MIC (not relevant): 0
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 23
    RSSI: -48 dBm
    Event counter: 1681
    Timestamp: 1491198514µs
    [Packet time (start to end): 152µs]
    [Delta time (end to start): 150µs]
    [Delta time (start to start): 230µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x9c124f94
    [Master Address: 52:12:d5:6c:bf:9a (52:12:d5:6c:bf:9a)]
    [Slave Address: f8:a4:c9:d7:48:fd (f8:a4:c9:d7:48:fd)]
    Data Header
        .... ..10 = LLID: Start of an L2CAP message or a complete L2CAP message with no fragmentation (0x2)
        .... .1.. = Next Expected Sequence Number: 1 [ACK]
        .... 0... = Sequence Number: 0 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 9
    [L2CAP Index: 60]
    [Connection Parameters in: 551]
    CRC: 0x38ef92
Bluetooth L2CAP Protocol
    Length: 5
    CID: Attribute Protocol (0x0004)
Bluetooth Attribute Protocol
    Opcode: Error Response (0x01)
        0... .... = Authentication Signature: False
        .0.. .... = Command: False
        ..00 0001 = Method: Error Response (0x01)
    Request Opcode in Error: Write Request (0x12)
        0... .... = Authentication Signature: False
        .0.. .... = Command: False
        ..01 0010 = Method: Write Request (0x12)
    Handle in Error: 0x0012 (Unknown: Unknown)
        [Service UUID: 25ae144105d34c5b828193d4e07420cf]
        [UUID: 25ae144205d34c5b828193d4e07420cf]
    Error Code: Unlikely Error (0x0e)

[Vidar Berg]

Please post the sniffer capture file.

[IvanR]

Im sorry but I can not share that file with you 

[Vidar Berg]

That is fine, but if you are unable to provide relevant information or instructions for me to reproduce the issue locally, I'm afraid there is not much more I can do to troubleshoot this further. I have already attempted to search for similar issues in our databases but have not found anything that resembles your case.