All HTTP sensors seem to fail when checked an https URL with a self signed certificate. The probes fail with PE105 No Response (-1) but when I change the URL to point to another of our servers with a signed certificate then the sensors work.
When monitoring a website on our IIS using PRTG's HTTP sensors, I get a PE105 "No Response" error
Modified on 2025-06-10 11:53:13 +0200
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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.
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.
Check IIS Configuration
This error is likely produced if the monitored website uses SSL and requires a client certificate.
Please check your IIS configuration as follows: In the Server Manager of the machine running your web server, in the Web Server (IIS)\Internet Information Services (IIS) Manager section, check the SSL Settings of the served website. Make sure the option Client certificates is set to Ignore.
PRTG's HTTP sensors do not have a client certificate build in, so the IIS just doesn't answer the requests if this option is set to either Accept or Require. This leads to the "no response" error.
May, 2011 - Permalink