3300345 - IQ 16.1 SP04.09 server hang, no user connections allowed

• Suddenly IQ server went to hang status.
• While the IQ hang, no new client session was established except dbo sessions.
• However internal operations like CheckPoint were running fine. 
• pstack:
  

  ..UnixTask::wait
  ..CondVar::wait
  ..Worker::yield_to_forbidding
  ..Worker::do_wait
  ..SocketIO::wait
  ..SysSocket::send
  ..c_strm_sock_pconn::blocking_put
  ..c_strm_tconn::tls_write
  ..SACI_WriteCallback
  ..dbc_writeCB
  ..dbc_TlsSessionWrite
  ..SACIStreamConn_Write
  ..TlsConnection::write
  ..c_strm_tconn::put
  ..c_strm_sconn::put
  ..c_strm_sconn::send_out_buff
  
  ..UnixTask::wait
  ..CondVar::wait
  ..Worker::yield_to_forbidding
  ..Worker::do_wait
  ..Worker::do_wait_for_netio
  ..EngStream::block
  ..SQLPresSendRaw
  

SAP IQ 16.1

CR827680, CR-827680, #827680, https, tls, socket, Chk, ChkDone, 'SocketIO::wait', 'c_strm_tconn::tls_write', tls_write ,  , KBA , BC-SYB-IQ , Sybase IQ , Known Error