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I see the error, 'Activation failed: please make sure serial number is valid. You can also check the Hub log or contact Unity support.'

Updated

The "serial number invalid" error in Unity can be caused by license expiration, authorization issues (e.g., expired access tokens), or network errors like ETIMEDOUT and ENOTFOUND. Troubleshooting includes checking internet connectivity, firewall/proxy settings, flushing DNS cache, and updating Unity Hub. If issues persist, users should contact support with log files from specified locations on Windows, Mac, or Linux.

Cause:

There are many causes for a license to appear invalid; the only way to diagnose your exact problem is by examining your log files. The most common causes of this error are:

  • License expired
  • Authorization issues:
    • Usually signaled by the error, "Access token is expired, attempting to get a new one with refresh token" and "403 Forbidden" appearing in the logs with multiple retries.
  • Network errors:
    • ETIMEDOUT appearing in the logs suggests that the Unity Hub is unable to establish a connection to certain servers.
    • ENOTFOUND appearing in the logs suggests the system is unable to resolve Unity’s servers' DNS names. This could suggest a DNS misconfiguration on your machine or network.

Recommendations:

Because networks and machine configurations can vary dramatically from person to person, Unity can only provide suggestions for resolutions rather than fixes. However, below are some common troubleshooting steps to try:

Authorization and network issues

  1. Check network connectivity: Ensure your machine has an active and stable internet connection.
  2. Check for firewall or antivirus settings that may block Unity Hub.

  3. If you use a proxy server, ensure the Unity Hub has the correct proxy settings configured.

    The simplest solution is to add entire domains for the following resources in your exception list:

    • unity.com
    • unity3d.com
    • plasticscm.com
    • google.com
    • googleapis.com
    • microsoft.com
    • aka.ms

    If you want to selectively control the subdomains, add items from the table in the proxy exception manual page. See also: Using Unity through web proxies

  4. Flush DNS Cache and Verify DNS Settings: Run ipconfig /flushdns (on Windows) to clear the DNS cache and verify your DNS settings.
  5. Update the Unity Hub: Ensure that the Unity Hub is updated to the latest version.

Further information

If you continue to see errors when trying to activate your license after trying each troubleshooting step above, contact the Customer Experience team for further assistance, including your log files found in the file locations below for further assistance:

(Select View and tick the Hidden items checkbox if the files are hidden.)

The Hub log file (info-log.json): 

  • Windows: C:\users\<yourusername>\AppData\Roaming\UnityHub\logs
  • Mac: ~/Library/Application Support/UnityHub/logs
  • Linux: ~/.config/UnityHub/logs
Unity.Licensing.Client:
  • Window:C:\users\<yourusername>\AppData\Local\Unity\Unity.Licensing.Client.log
  • Mac: ~/Library/Logs/Unity/Unity.Licensing.Client.log
  • Linux: ~/.config/unity3d/Unity/Unity.Licensing.Client.log

 

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