How to force the notification to turn on from the server not the client?

[June6]

uint16_t buffer[4];
	
buffer[0] = p_nus->handles1.cccd_handle;                  // cccd handle
buffer[1] = 2;                                            // cccd attribute size = 2
buffer[2] = 1;                                            // 1 = enable notifications
buffer[3] = crc16_compute((uint8_t *)buffer, 6, NULL);     // CRC-CCITT (0xFFFF)
err_code = sd_ble_gatts_sys_attr_set(p_ble_evt->evt.gap_evt.conn_handle, (uint8_t*)(buffer), 8, BLE_GATTS_SYS_ATTR_FLAG_SYS_SRVCS); 

if(err_code == NRF_SUCCESS)
{
    p_client->is_notification_enabled1 = true;  // Enable notification
}

I add this code in 'static void on_connect(ble_nus_t * p_nus, ble_evt_t const * p_ble_evt) '  on the sever. But I still got an err_code NRF_ERROR_INVALID_DATA. Softdevice is s132nrf52611. Any suggestions to force the notification? I use the SDK version 15.3.0.

[June6]

There is an error in the above description, softdevice is S140 nRF52840.