400 bad request response while uploading JSON files via HTTP API

Hi guys,

I have issues uploading my JSON files to Grafana via Insomnia(open-source API design and test tool). The pecular thing is that when I upload the following dashboard:

I can see my dashboard in Grafana, so far everything is cool. But when I copy the json model of the same dashboard and send it to Grafana again via Insomnia, I get a 400 bad request response:

Now it dosent even say that the dashboard already exists. It just says 400 bad request. What do you think is the problem here? But are valid json files. I already checked their validity.

Are you providing all the necessary parameters?