If the port is already occupied (as in the screenshot), prompt as in below message will appear.
Case 1: If the application is running in the services and you try to start the application in CMD as well this error occurs ,if the application is started in the services then stop the application in the command prompt.
Case 2: If you still face issues follow the below steps to find application that uses the port
>>Open the CMD as an administrator and execute the command NETSTAT -ano | findstr 443. This command will display the processes and the ports used by them.
>>To find application that uses the port. Go to Task Manager>>Details>>Search with the PID number and find which service is using the port ,killing it may cause any server level changes so please contact your system administrator about this and try to free up the 443 port or change the port number for the existing service using the port 443.
Once the port is freed up then the application will start running.
>>Follow the below link to change the web server port.