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Resolving IIS 10.0 Site Start Error: 'Another website may be using the same port'

Posted by AlbusBit on April 18, 2023 · 4 min read


Internet Information Services (IIS) is a popular web server on the Windows platform, often used to host websites and applications. However, when setting up a new site on IIS, you may encounter an error message stating "The website cannot be started. Another website may be using the same port." In this blog post, we will discuss the reasons behind this error and provide a step-by-step guide to resolve the issue.


The error message usually occurs when two or more websites or applications are configured to use the same port (e.g., port 80 or 443). In our specific scenario, we created a new site with a binding for http:*:443: on IIS 10.0, deleted the default site, and restarted the server. However, the new site cannot be started due to a port conflict, despite netstat showing that no process is using port 443.


To resolve the issue, we will first check for any processes using the same port using the netstat command, and then follow the troubleshooting steps outlined below.

  1. Identify the process using port 443:
    • Open the Command Prompt as Administrator.
    • Run the following command to list all processes using port 443: 'netstat -aon | findstr :443'
    • Note down the PID (Process ID) of the process using port 443, if any.
  2. If you find a process using port 443, follow these steps to stop or change the port:
    • Identify the process by PID using Task Manager's 'Details' tab.
    • If the process is a service, stop it temporarily or change its listening port via the Services management console (services.msc).
  3. Double-check your site's bindings:
    • Open the IIS Manager.
    • Select your site and click 'Bindings' on the right-hand side.
    • Make sure there's only one binding for http:*:443: and it is using the correct protocol (usually, HTTPS should be used for port 443).
  4. Check the SSL/TLS settings:
    • If you're using HTTPS for the binding, make sure you have a valid SSL certificate installed.
    • Open the IIS Manager, click on your site, and then click 'SSL Settings' in the middle panel.
    • Configure the SSL settings according to your requirements (e.g., require SSL, ignore client certificates).
  5. Check the application pool:
    • In the IIS Manager, click 'Application Pools' in the left-hand panel.
    • Make sure the application pool associated with your site is started. If it's stopped, right-click it and choose 'Start'.
    • Check the application pool's settings, such as the .NET version, to ensure they match your site's requirements.
  6. Verify that the World Wide Web Publishing Service is running:
    • Press Win+R, type 'services.msc', and click 'OK' to open the Services management console.
    • Locate the 'World Wide Web Publishing Service' in the list, and ensure it's running. If not, right-click it and choose 'Start'.
  7. Check the event logs for errors:
    • Open the Event Viewer (Win+R, type 'eventvwr.msc', and click 'OK').
    • Look for any errors related to IIS, your site, or the application pool in the 'Application' and 'System' logs. These errors might provide more information about the issue.
  8. Test the site on a different port:
    • As a last resort, try changing the binding port for your site (e.g., to 444) and see if it starts successfully. If it does, there might be a hidden conflict or an issue with port 443.


By following the steps outlined in this blog post, you should be able to resolve the "Another website may be using the same port" error in IIS 10.0. Using the netstat command to check for processes using the same port is a crucial first step. Then, ensure that your site's bindings, SSL/TLS settings, application pool settings, and the status of the World Wide Web Publishing Service are properly configured to avoid conflicts and ensure a smooth setup process.

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