Yeah, I only added VERSION: 2 to see if that would help. Removing it or even explictly stating VERSION: 3 doesn't work.

I was wondering if curl had something to do with not all header fields going through, which is why it only recognises the invalid API key if I remove everything else ... they seem to be there in netmon but "Header Length" is 20? That doesn't seem right.

...

+ Versions: IPv4, Internet Protocol; Header Length = 20

...


Accept: application/json; charset=UTF-8
VERSION: 2
X-IG-API-KEY: e6329bb0b1e25e9bb3b57c4cd3070a2a95a60d7f
ContentLength: 52
HeaderEnd: CRLF

...