Embeded iFrame URL does not work via curl, does work in browser [solved]

I have an embeded chart (e.g. https://foo.bar.co.uk/d-solo/F…) that loads fine in Firefox.

If I open the network browser, right click the request and “copy as cURL”, then use the returned HTML in a stand alone HTML page, it loads Grafana but says " Page not found 404 error" with a green chart under it i.e. the Grafana 404 page, not an error or anything.

There are not signs of other failing network requests.

What could be causing this ? What state does Grafana have that isn’t in the network request ?!?

Oh well :