If you happen to run into problems with getting your code to execute in the simulator, it could be because of one of the following reasons: 1. The simulator is not turned on, i.e. the Play button is not pressed. 2. There is a mismatch between the ports that are being specified in your code, and the ports that your simulated robot is using. To fix this issue, follow these steps below: Select the robot in the simulator Open it’s Object Properties (a) Expand the EV3 label (b) Observe the ports on the digital brick that are being used. (c) Open the LEGO programming environment, and check that what is being specified in your move and sensor blocks match with the simulated robot’s object properties.