Port 4004 may already be in use, you can terminate the process occupying it by following these steps:
To preview your application, go to the Run Cofigurations, and select S4HANA_Joule_SalesOrder => Run Application.

Select the Sales Orders App Web Application.

Select Settings.

Select all columns. Select OK.

Select Go.
Review the Sales Orders application you’ve just built.

Congratulations! You have successfully built and previewed a CAP application using SAP Build Code powered by Joule copilot!