What is this?

This knowledgebase contains questions and answers about PRTG Network Monitor and network monitoring in general.

Learn more

PRTG Network Monitor

Intuitive to Use. Easy to manage.
More than 500,000 users rely on Paessler PRTG every day. Find out how you can reduce cost, increase QoS and ease planning, as well.

Free Download

Top Tags

View all Tags

HTTP Full Web Page sensor is “unable to navigate”. What can I do?



When I use the HTTP Full Web Page sensor, I get the error message Unable to navigate (ERR_NAME_NOT_RESOLVED).

Where does this error come from? Are there any specific settings to consider regarding the probe system?

chromium error error-messages http http-full-web-page nla phantomjs prtg

Created on Mar 4, 2014 3:45:25 PM by  Gerald Schoch [Paessler Support]

Last change on Jan 4, 2023 11:51:18 AM by  Brandy Greger [Paessler Support]

3 Replies

Accepted Answer



This article applies as of PRTG 22

HTTP Full Web Page sensor: “Unable to navigate

The HTTP Full Web Page sensor can load web pages via one of the three browser engines Chromium, PhantomJS, or Internet Explorer. We recommend that you use the Chromium engine, but depending on your case, the other engines can also be a good choice.

If you added an HTTP Full Web Page sensor to PRTG but it does not work, check the following system settings and adjust them respectively. A typical error message for this sensor is Unable to navigate (ERR_NAME_NOT_RESOLVED). Note that this error also appears if PRTG cannot reach the given URL, which is why you should check it first.

System settings for the HTTP Full Web Page sensor

If you create an HTTP Full Web Page sensor, consider the following settings on the probe system:

Graphics card settings (Chromium and PhantomJS)

For the HTTP Full Web Page sensor, the settings of the graphics card on the probe system are relevant. If you use, for example, an NVIDIA or ATI graphics card (and the following setting is available), disable the power-saving graphics processing unit (GPU) and instead use the high-performance processor.

To change this option for NVIDIA, see this article: Google Chrome crashes when viewing maps. What can I do?. For ATI, go to the Catalyst control panel and select High Performance.

Probe on Windows 7 (Chromium)

If your probe runs on a Windows 7 system, you must scan it at least once for the Windows Experience Index:

  • Open the Windows control panel (click the Start button, then select Control Panel).
  • Select System | Check the Windows Experience Index.
  • Start the scan.

Activate NLA

No matter which web browser engine you use, make sure that the NLA (Network Location Awareness) service is running. To do so, open services.msc on the probe system and start the NLA service.

Created on Mar 4, 2014 3:49:50 PM by  Gerald Schoch [Paessler Support]

Last change on Jan 3, 2023 9:49:18 AM by  Brandy Greger [Paessler Support]



interesting NLA is required, and its disabled in our network as security best practice?

Created on Jul 26, 2022 11:00:55 PM



Hi there,

I'm afraid there is no best practice from our side besides the article above.

Kind regards

Felix Wiesneth - Team Tech Support

Created on Aug 1, 2022 7:03:45 AM by  Felix Wiesneth [Paessler Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.