Postman works - but neither HTTParty nor curl -what is wrong?

[wdiechmann]

I am painfully aware that this is about the worst title ever - allow me to elaborate:

I have this endpoint that works when using Postman - but when I pick code|curl I get

curl -k -X --location 'https://unifi.thisted-gymnasium.dk:8443/api/login' \
--header 'Content-Type: application/json' \
--header 'Cookie: unifises=uIRJP15glppYbjD3ObVQJyPdC97ZNnM6' \
--data '{ "username": "unifi-portal", "password": "UniPass2025()" }'
{"meta":{"rc":"ok"},"data":[ ] }%      

but if I remove the Cookie header (which in reality I'd not have available) - I cannot login using curl, and trying to 'emulate' this in HTTParty gives me

response = HTTParty.post(
  "https://a.url.tld:8443/api/login",
  body: { username: "uname", password: "pword" }.to_json,
  headers: { "Content-Type" => "application/json" },
  verify: false 
)
 {"meta" => {"rc" => "error", "msg" => "api.err.Invalid"}, "data" => []}

and I have tried with RestClient and Faraday as well, which sadly reports exactly the same - leading (ChatGPT and) me to conclude that it's deeper into the stack somewhere - but where?

Does anybody have a clue - perhaps a link that could push me in the right direction (hrs of googling and prompting has lead me nowhere)
😢