This article applies as of PRTG 26

Automatic license activation in proxied environments after a PRTG core server restart

If you have a Paessler PRTG Enterprise Monitor license and use a proxy server, you might encounter issues with the automatic license update and activation. For example, you might see the following error message: 

License has expired. (Failed to establish secure connection Socket Error #10060 Connection timed out.)

There is a known issue that PRTG cannot access your proxy settings after the PRTG core server restarts.

Workaround

  1. Go to Setup | System Administration | Core Server in the PRTG web interface.
  2. Confirm that the proxy configuration is correct. Correct the settings if there are incorrect.
  3. Restart your PRTG core server.
  4. Go to System | License Information.
  5. Click Update License to manually update and activate your license.

This way, PRTG can access your proxy settings and the automatic license update works until the next PRTG core server restart.