The reason for the failure. Possible reasons include: 1 = other (error which cannot be classified in any of the types listed below). 2 = internal error occurred 3 = failed to authenticate the peer/user 4 = failed to authorize the peer/user 5 = system capacity exceeded (memory, cpu, max users etc) 6 = peer requested to abort the session or the setup 7 = lost peer's heartbeat 8 = local management request.