I am trying to monitor an XML file via HTTP using the HTTP XML/REST Value sensor, but the sensor returns an error The server committed a protocol violation. Section=ResponseStatusLine

The webserver's response is invalid. However, you can configure the sensor to use a more tolerant behavior. To do so, please create a new text file, containing

<?xml version="1.0"?>
<configuration>
<system.net>
    <settings>
        <httpWebRequest useUnsafeHeaderParsing="true" />
    </settings>
</system.net>
</configuration>

Save it as XMLValue.exe.config and copy it to the Sensor System sub-folder of your PRTG program directory.

Then the sensor should work as expected.

Note: As of PRTG version 9.1.4.1839 (Nov 15th, 2011) this work around is not necessary any more.


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.