Web server failed to start. Port 8013 was already in use.

There could be several reasons why the web server failed to start and the port 8013 was already in use. Here are a few possible causes and solutions:

1. Another process or application is already using port 8013: You can use the following command to check which process is using the port:

   netstat -ano | findstr :8013

Once you identify the process, you can either terminate it or change the port number for your web server.

2. The web server is already running: It's possible that the web server is already running in the background, and you are trying to start another instance on the same port. You can stop the existing web server process or choose a different port for your new instance.

3. Port 8013 is reserved by the operating system: Some ports are reserved by the operating system and cannot be used for custom applications. You can try using a different port number, preferably one above 1024.

4. Firewall or security software is blocking the port: Check your firewall or security software settings to ensure that port 8013 is allowed for incoming connections.

By troubleshooting these potential issues, you should be able to resolve the problem and start the web server successfully.