DYK: Why won’t the Authentication Proxy service start?

If the Duo Authentication Proxy service won’t start, you might be stuck wondering what to do. There is a guide in the Duo knowledge base that explains how to troubleshoot the possible reasons why this can happen, and we will also be sharing some of those reasons here today. This is a question that commonly comes up in support cases and here in the Community.

You can usually determine the source of the problem by looking at the Windows Event Viewer logs. For details on how to do this, please consult the guide linked previously. Some of the more commonly seen errors when this issue occurs are as follows:

  • “Access is denied”
    • This error can occur if you did not install the Authentication Proxy as an administrator. You will need to uninstall, then choose “Run as administrator” when you reinstall the Authentication Proxy.
    • You might also see this error if a custom service account you’re using to run the Authentication Proxy service doesn’t have the proper privileges to write to the Event Viewer or the ‘log’ folder used by the Authentication Proxy. You can follow the steps in the article on how to address the permission requirements for the service account.
  • “The service did not respond to the start or control request in a timely fashion”
    • This may be caused by underlying issues with the OS. To resolve this in Windows, navigate to the Service properties and General tab and set the “Startup type” to “Automatic (Delayed Start)”. More information can be found in the Microsoft documentation on delayed start.

Be sure to check out the help article and troubleshooting guide for more tips on how to solve this issue!