Synthetic Classic has reached end of support and is no longer available. Existing Synthetic Classic customers have been upgraded to the all-in-one Dynatrace software intelligence platform.

Troubleshooting Private Last Mile runtime issues

Suggested resolutions to common runtime issues are provided below.

For answers to question about Private Last Mile data, check the Knowledge Base.

The message “error communicating with server. retrying” appears.

This message indicates that something is blocking the peer agent from communicating with the Synthetic Classic server. If you are seeing this message when you install the peer, there is probably a firewall blocking the traffic. The peer must be able to send HTTPS requests to the following servers:


Occasionally you will receive this message when there is a Synthetic Classic server outage that will be resolved shortly. If the problem persists and you have a proxy server, your peer may not be configured to use your proxy server. Review the proxy settings in the Preferences dialog box. For more information, see Configuring Private Last Mile.

The private peer doesn’t run after the Windows account password is changed.

The private peer is configured to run under a Windows administrator account. If the Windows account password is changed, the password must be updated for the private peer service (gomezpeer):

  1. In the Windows Control Panel > Services, right-click Gomez peer and select Properties from the context menu.
  2. In the Gomez peer Properties dialog box, select the Log On tab.
  3. For This account, update the Password and Confirm password fields.
  4. Click OK to save the changes.

A Java error occurs with LIBNSPR4.DLL.

This error usually means that other instances of the JVM are running that are preventing the peer from running properly. Use the Windows Task Manager to end any Java program that may be running, then try initializing the peer agent again.

The Private Last Mile machine continues to return “userscript error” when other machines do not.

Check whether the script uses GomezGlobalFunctions. If it does, check the cache subdirectory in the Private Last Mile installation directory for GomezGlobalFunctions.008.js. Replace this file with the file from

The Synthetic Classic Portal page shows an error.

Try the following:

  • Check the steps to reproduce the error.
  • Verify that the error occurs in your own browser.