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 Sensor Issue After Upgrading to Version




After upgrading PRTG to version, one of our HTTP sensors is no longer working and throws an error message of:

HTTP/1.1 406 Not Acceptable

The sensor had been working prior to updating PRTG to version The endpoint that we're monitoring is a Kubernetes RESTful API that just returns a JSON-formatted page with component status. It uses a self-signed certificate and we can browse to the endpoint with Google Chrome and MS Edge without any issues and get a 200 response in those respective browsers.

Can you please offer any insight into how to resolve this issue?


406 http-1-1-406-not-acceptable http-sensor latest-prtg

Created on Jun 27, 2022 11:18:07 PM

2 Replies



Hi there,

Thank you very much for your contribution.

In such cases, please directly contact out support team through our Helpdesk Portal. Please also attach screenshots of your faulty HTTP sensor and its settings so we can refer to the described scenario and also have a look at your current sensor configuration. Those things are much easier provided on the Portal than on the Knowledge Base.

Thank you,

Created on Jul 13, 2022 8:25:19 AM by  Sebastian Kniege [Paessler Support]



We had a similar issue - changing the HTTP Monitoring Engine from Default Engine to Compatibility engine seems to work.

Created on Aug 4, 2022 9:39:27 AM

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.