I am trying to work with L2CAP channels over BLE. The service discovery, PSM lookup (via characteristics) and such all work fine. The channel connects and I am able to exchange a couple of packets before the input stream is closed unexpectedly. Meanwhile, the console reports the following CoreBluetooth messages: error WARNING: Unknown error: 431 error WARNING: Unknown error: 436 As far as I can tell these error codes are undocumented and the L2CAP documentation is scarce at best. Does anyone know what they mean?