This article provides steps to troubleshoot and resolve the license errors -17 and -111 encountered in NetSim Lite when attempting to connect to the license server. 


Important: Try Connecting from a Different Network

This error is commonly encountered on organizational or corporate networks, where firewall or security settings may restrict access to certain ports. To cross-verify or resolve the issue:

  • Try connecting to a personal network such as a mobile hotspot or home Wi-Fi. This can help determine if the issue is network-specific and bypass potential restrictions on the organizational network.


Solution Steps:

  • Verify Internet Connection
    Ensure that your device has an active and stable internet connection. NetSim Lite requires internet access to validate its license with the server.

  • Check Firewall Settings

    • Confirm that your firewall is not blocking NetSim Lite's communication ports.
    • Allow port 5053 and port 5258 through your firewall. These ports are essential for NetSim Lite to communicate with the license server.
  • Proxy Configuration (if applicable): If your network uses a proxy server, verify that the proxy settings permit traffic on ports 5053 and 5258. You may need to adjust your proxy or consult your network administrator.
  • Restart NetSim Lite: After adjusting your network settings, restart NetSim Lite and attempt to reconnect. This ensures that any changes take effect.
  • Additional Network Checks

    • VPN Connections: If you're using a VPN, try disconnecting, as it may interfere with the license server connection.
    • Antivirus Software: Some antivirus programs may block network connections. Temporarily disable them to see if it resolves the issue.
  • Contact Support
    If the error persists after following these steps, please contact our support team:

    • Email: [email protected]
    • Information to Provide:
      • A screenshot of the error message.
      • Details about your operating system and network setup.
      • Any firewall or antivirus software you are using.