Power automate / webhook : webhook response status 400 bad request

I’m trying to set up a webhook to send a notification to Power Automate, but I get an when trying a test notification.

This is what I do in Power automate :

  • create a new trigger : “when we receive a HTTP-request”
  • There I get an URL for the HTTP GET
  • This URL I then try to fill in in Grafana under new contact point

But when pressing “test” I get this error.

What am I doing wrong?