No ATT channel for MTU 43

[Rakshita]

I am testing peripheral UART sample code with nrf5340DK along with some other device. I have connected the UART pins of that device with nrf to receive its data.

I am continuously getting 

00> [00:04:27.891,754] <wrn> bt_att: No ATT channel for MTU 43
00> [00:04:27.891,784] <wrn> bt_gatt: No buffer available to send notification
00> [00:04:27.891,784] <wrn> peripheral_uart: Failed to send data over BLE connection

this. I tried to change the MTU size as well by adding: 

CONFIG_BT_BUF_ACL_RX_SIZE=251

CONFIG_BT_BUF_ACL_TX_SIZE=251

CONFIG_BT_L2CAP_TX_MTU=247

CONFIG_BT_CTLR_DATA_LENGTH_MAX=251 these commands in prj.conf but it didn't work.

What should I do?

[Amanda Hsieh]

Hi, 

Which NCS version are you using?

Did you set configs for the net core as https://github.com/nrfconnect/sdk-nrf/blob/main/samples/bluetooth/throughput/child_image/hci_ipc.conf?

Regards,
Amanda H.