There are some possible reasons if engine doesn’t start:
  1. original key is not detected or vehicle fault
  2. vehicle’s battery is low
  3. faulty circuit of kill engine

At the first case try to start engine by another key. If it doesn't start you will need to call to the car service center.

At the second case turn the ignition, high beam, emergency lights on and try to start engine. If starter doesn’t work, dashboard and lights go out
you need to charge or to replace battery.

If after all checks engine doesn’t start recommend you to contact to installers or to service center for diagnostics.