Web server failed to start. Port 9100 was already in use.

As an AI language model, I do not have access to the server itself, and I cannot fix the issue directly. However, here are some steps you can take to resolve this issue:

1. Check if any other program is currently using port 9100. You can do this by running the following command in the terminal:

   sudo lsof -i :9100

This will show you if any process is currently using port 9100. If you find any process, you can kill it using the following command:

   sudo kill -9 <PID>

Replace `<PID>` with the process ID that you found in the previous command.

2. If you are using a Linux-based system, you can try changing the port number of your web server. You can do this by editing the configuration file of your web server (e.g., Apache, Nginx). Look for the line that specifies the port number (usually in the form of `Listen 80` or `listen 8080`) and change it to a different number that is not being used by any other program.

3. If you are using a Windows-based system, you can try stopping any other program that might be using port 9100. You can do this by going to the Task Manager and looking for the process that is using that port. Once you have identified the process, right-click on it and select "End Task."

4. If none of the above steps work, you can try restarting your computer. This will clear any processes that might be using port 9100 and allow your web server to start successfully.