How to enable the Data extension feature in Bluenrg2?

[Padmashree_NS]

While sending more bytes of data from app to the BLE module after connection I am getting the following error-

Error 13 (0xd): GATT INVALID ATTR LEN

How do I increase the length so that I can send more bytes of data?

[MBRAI.9]

Hello, I'm trying to send long packets (> 20 bytes), so I added a custom service with characteristic supporting notification and indication with a size = 40 bytes.

After connection established, I send a LL_LENGTH negotiation to update the TxOctets to 40 bytes (using hci_le_set_data_length api)

The remote master configured the characteristic to notify.

I tried then to send a notification of 40 bytes ... only 20 bytes were sent.

I also tested to use hci_le_write_suggested_default_data_length api before the connection establishment, the negotiation was done successfully, but unable to send packets > 20 bytes

what is missing to be able to send packets > 20 bytes ?